 
### Nature Writing

Richard Herley

Smashwords Edition

Copyright 1984-2010 Richard Herley

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Cover image: Cley Mill, Norfolk

**Table of Contents**

Introduction  
The Geese of Oxhey  
In the Valley  
Defending a Territory  
Giants and Pygmies  
Ancient Aviators  
Flaunden by Night  
Secrets of the Goldeneye  
At the Ford  
Up from the Pit  
The Red and the Grey  
Open All Hours  
Bird Song  
White's "Selborne"  
Staines Reservoir  
A Moorhen  
Frogs  
Wind  
The First Chiffchaff  
Hares  
Herons  
Croxley Moor  
Bumblebees  
Introduced Trees  
Tring Reservoirs  
Hydra  
Bluebells  
Swallows  
Plant Odours  
Weasels  
Glaciers  
Badgers  
Snails  
Lapwings  
The Aquatic Ape?  
Nettles  
Preening  
Lichens  
Dragonflies  
Balsams  
Spotted Flycatchers  
The Moon  
Black-headed Gulls  
Aristocrat Butterflies  
Collared Doves  
Fungi  
Sleeping Rough  
Stocker's Lake  
Leaf-fall  
Mandrake  
Moles  
Hunting Sparrowhawk  
Linnets  
Brent Geese  
Unchanged Selborne  
Words from My Nature Journal

Introduction

My enthusiasm for natural history was probably first sparked by Richard Jefferies, whose _Bevis_ fevered my imagination for two or three months in 1962, when I was twelve. My recreational reading consisted thereafter mostly of books about nature. Many of these I bought with my pocket money, so they tended to be second-hand and out of date.

British nature-writing reached its heyday in the late nineteenth century. The drift to the cities had produced a rich vein of nostalgia for the countryside, and this was assiduously mined by the publishers of the day. Besides essayists like Jefferies and W H Hudson there were any number of authors who produced handbooks of the flora and fauna. All these books were written in a formal style and edited to Victorian standards of literacy. I didn't realize it at the time, but they were having a profound influence on the way I produced, and was ever to produce, written English.

Nature as a subject for a child's pen is ideal: it is inexhaustible. There is also scope for original observation and plain description, especially if the child is lucky enough to have been born into a literate household and attends a school whose teachers have high expectations of their pupils.

The first part of this collection comprises a series of articles published during 1984-5 by a local newspaper in my home town, Watford, on the outskirts of north-west London. After these are four short pieces I wrote purely for pleasure. These begin with _Hunting Sparrowhawk_.

Finally I provide a series of brief extracts – often no more than a sentence or two – from the nature journal I have been keeping since 1963. Read in sequence, these provide a curious picture of a boyish enthusiasm gradually maturing. They also give a glimpse of a disappearing world. Alas, my old school is by no means what it was, children are no longer free to wander the woods and wild seashore at will, and the English countryside is even more degraded now than it was then.

Richard Herley, December 2010

The Geese of Oxhey

Lying in bed, you hear it approaching from a great distance: a mad, clamorous honking as of two hundred unreasoning taxi drivers caught in a jam, but the horns are all mobile and airborne and pass just above the rooftops and on their way. You turn over and try to get back to sleep. There is nothing you can do about the noise, or the fact that it has woken you at daybreak many times before. If you live anywhere in Oxhey or West Watford or Rickmansworth you must resign yourself to the knowledge that you have geese for neighbours.

They are Canada geese, big, handsome birds, brown and black and white. The flock numbers two or three hundred, and spends its time in a selection of favoured spots up and down the chain of gravel pits between Oxhey and Denham. The geese are discerning gourmets. They know all the choicest pastures. One of their favourites is the broad expanse of playing fields at Merchant Taylors' School. There, while one or two keep watch with upraised necks and black, suspicious button eyes, the rest are browsing by the running track, expertly cropping the grass to a regulation length. It is an hour after dawn, a time at which, even in the autumn, few people are about. The sky is blue; the distant school, the cricket pavilion, the black, sawn-off uprights of the rugby goalposts standing about here and there on the field, are all made indistinct by mist. The geese continue to feed. The turf is littered with their large, greenish mutes; the flock has advanced across the running track, and crumbs of white adhere to some of the dark, webbed feet.

Suddenly another neck goes up, and another, and yet more. On the far side of the field, where the path adjoins the netting fence, the sentinels have seen the feared and hated shape. A man. With him is a lesser animal, a dog. The geese know what that is.

They wait, growing more restless, as the man approaches. He is walking through the dew, wearing gumboots and a green coat. He throws a stick and his dog runs for it. Now the geese are distinctly unhappy. One begins to honk, and others take up the complaint.

The dog is within a hundred and fifty yards, and behind the dog is the man. The dog makes a dash for the birds: in a rush of wings and honks they are taking flight, two hundred times fifteen pounds or more of goose. A ton and a half of them gaining air and space. From behind you can see the pattern made by their rumps and inner and outer tail feathers: intense black, a broad crescent of purest white, more black. The pattern is barely visible on the ground. It is made to be seen only in flight, a warning, an alarm signal, or something to follow, holding the flock together in its journeyings.

These geese are not truly wild. They live as wild birds, but their forefathers were captives on ornamental lakes. Before that they really were wild, in North America, which is where each autumn the Canadas still travel down from the Arctic states to winter in Mexico and along the Gulf. In New England at this time of year the geese are passing through; in Old England they have no intention of going any farther than over the hedge and away from the man and his labrador.

They circle the gravel pit and make as if to settle; but then, at some mysterious signal, a decision is made and they circle again, settling instead on the adjoining water of Hampermill Lake. By now the honking is reaching its climax. The other, more sober, birds of the lake – the solitary heron standing on a log, the grebes, the parties of mallard and shoveler – refuse to take note of the fuss. They have heard it all before. The geese are swimming about; some have climbed the bank and are already inspecting the pasture there. But the grass by the lake is inferior, fit only for the coots and moorhens to graze. Better pickings are not far away, just over there at Brightwell's Farm, not a furlong from the northern margin. In groups of five, ten, twenty, thirty, the geese leave the lake, rise just enough to clear the yellowing hawthorn trees of the hedgerow, and settle once again to feed.

In the Valley

They were once the masters of the dank, damp places, undisputed lords of the river. They were magic and to be feared. If you were so brave as to cut one down the stump bled. The timber did not rot. The foliage was dark, the bark black, so black that, even in winter when the leaves had gone, the ground under the alders was always gloomy and oppressive.

The alders were here, of course, thousands of years before we were. Their pollen has been preserved in samples taken from peat bogs; their seed has been found among the earliest remnants of ancient man. At that time the whole of England was one vast forest. The dry ground was the scene of a strange, imperceptibly slow and protracted yet ferocious war of attrition waged between several species of trees. The prize was the possession of the landscape: the winner, in the first age, was the small-leafed lime. Then came men with their animals. Lime leaves were gathered as fodder. The lime's defences were weakened and in came oak. Oak forest dominated England until the arrival of metal and the growth in the human population signalled its end.

But below all this, in the marshy places, where the soil was too wet to interest the farmers, the alders were yet safe. They survived here using the same weapon that had held off the limes and oaks: a special sort of root system that produces its own free nitrogen and enables the roots to withstand prolonged or even permanent immersion. The roots, together with the unique mixture of sedges and rushes that accompanies alder woodland, gradually consolidate the marsh, raising the level and sending the water elsewhere. Once the best ground higher up had been put to the axe, we began to drain the water-meadows, and to maintain this drainage the alders had to go.

Extensive alder woodland, or alder carr, as it is called, is now virtually unknown in England. The few alders that are left to us are thinly scattered along the margins of lakes and rivers, and only survive there by default. They are given gracious permission to remain, to represent their ancestors in the valleys where once they held sway. There is something sad about them now, as though they cannot forget past glories. The aluminium sign, _PRIVATE FISHING, NO DAY TICKETS, BY ORDER_ , the two iron nails unfeelingly driven into the heartwood and allowed to rust, are just another humiliation, too minor even to notice or resent.

Even the river itself has been destroyed, an impossible act in the imagination of the ancestors. It is now a canal. The otters have gone, the trout, the variety of dragonflies. From the old times only the siskins really remain, ever faithful: small, acrobatic finches, streaked green, yellow, and black. With goldfinches and sometimes redpolls and blue tits they make flocks that move through the alder tops, prising the seed from the small, woody, cone-like lanterns of the old female catkins. The seed is rust-coloured and rich in oil, very nourishing for the finches on a dark November afternoon such as this. The siskins are especially busy, preparing for a long and chilly night spent immobile, losing heat, roosting high up in the alder branches. Their cry is a thinner, more metallic, version of the greenfinch's wheeze, quite unmistakable, even when you and your bicycle are jolting and crunching along the towpath. You stop and look up, hoping for a glimpse of them at work. Alder seed is coming down in sparse showers. The seeds will float away if they hit the canal. Small as they are, much of their surface is given over to two minute waterwings. It must be hard work to eat enough to make a meal, but the siskins do it. In this, like the alders themselves, the siskins are too narrow and specialized. That is why they are relatively uncommon these days, much less plentiful than the goldfinches. The siskins' diet is virtually restricted to the seeds of alder, birch, and of a few other trees; the goldfinches can take many other sorts of food besides: thistle and burdock seed especially, insects too. And, even among the alders, the goldfinches are more enterprising and opportunistic. At this very spot last winter a party of goldfinches was on the ice, picking up the alder seed where it had fallen. In this way the goldfinches saved themselves their usual exertions, and the food needed no special finding. It was there, spread out as though on a table.

The siskins are moving on. Dusk is approaching and you have only dynamo lights, not the safest way to illuminate rough ground, so perhaps you had better do the same.

Defending a Territory

"I own that I love the blackbird," says one nineteenth-century writer: an easy confession to make. But who will speak up for that other black bird, the carrion crow? From time immemorial it has been called villain, associated with midnight and the darkest deeds. It seems to have a penchant for the graveyard and the cypress. It is drawn by the smell of death. One New Year's Eve, at dusk, I witnessed a pair attacking the eyes of a sickly herring gull, one bird leaping forward to deliver a savage and cowardly blow as the other leapt back. In ten minutes the gull was killed, and at leisure the crows picked out its brains.

Yet the gull was anyway long past hope. Left alone in the soft mud at the centre of a drained reservoir, it would have attracted a worse horror still: rats. Its time had come. The crows gave it a quicker and more merciful end.

Like undertakers, crows are always properly dressed. With them blackness reaches an art. Every outward inch is black, excepting only the small white eyelid. Science suggests that black plumage is more resistant to wear, but there is something else at work in the design of a crow. Blackness is not a true quality; rather, it indicates the absence of light. The crow's feathers absorb every last photon, except in the most brilliant sunshine, when the mantle gives back a grudging, oily blue sheen.

A pair of crows seen like this on the soft, lush sward of the town park is a sight to be prized. The two birds have been faithful to each other for several years now. In the early spring they usually build on a previous nest, high up in the fork of one of the red oaks. There, safe from small boys and the thousand disturbances below, the female alone incubates the single brood of four or five young. She is fed and protected by her attentive mate, who later supplies the food for her to give to the nestlings. At a later stage he is allowed to feed them too. A month or so after hatching the young ones fly. Until autumn they remain with their parents, learning the business of being a crow, and then are driven off.

A crow cannot breed unless and until it has a territory. In size territories vary from about 35 to 110 acres, defended most vigorously at or near the nest site. The immature birds, once expelled from the family group, have nowhere to call their own. They join a wandering gang made up of other young birds and rootless adults. This non-breeding flock lives on the fringes, continually invading the territories of the breeding pairs.

Birds holding territory dominate those that do not. Males dominate females; to the male of the pair falls most of the work of defence. Single invaders are usually easy to expel, but when there are more, the female must join in as well. If the intruders become persistent the home birds must use their full armoury of threat postures, cawing displays, aerial chases, and the technique of supplanting, or dislodging the intruder from its perch. Disputes rarely come to blows, but it can be weary work for some pairs and their health and breeding success suffer as a result. In winter the non-breeders fly off at dusk to join the communal roost of rooks and crows in the woods, but the home birds must remain behind till darkness is almost complete, and in the morning they must get up fifteen minutes early to hurry back in readiness for the day's defence, signalled by a rolling peal of _krah_ s from the topmost twig of the highest tree.

There are moments of peace, however and, at the edge of the territory, our birds tolerate and are tolerated by their territory-holding neighbours. The neighbours are less of a threat than the feckless ruffians of the non-breeding flock. The territories even overlap to some extent in a common region – like that by the asphalt path where a woman is pushing her twins in a double buggy. The crows watch from a distance, with a mixture of suspicion and disdain. They have been digging for invertebrates, and by the rustic shelter a little while ago they found and ate the remains of a cheese and chutney sandwich.

The woman and her nestlings draw nearer. There is no real need, but for appearances' sake the male crow takes wing. Followed by his mate, he flies low for fifty yards and pitches on a fresh patch of ground, to see what a little more digging will bring.

Giants and Pygmies

Not far from the lane is an area of the wood that a Georgian forester must have thought suitable for Norway spruce. He may have dreamed of leaving them to his grandson's son to sell as masts for sailing ships, or simply as the raw material of the new literacy. He planted well; his trees grew strong and tall, but as they grew the markets changed. Steam replaced sail; cheaper woodpulp came from Scandinavia. The trees matured and were not harvested, and yet lived on.

Now many of these giants are reaching their term. Some are dead already, the bark peeling, the exposed heartwood bleaching grey, the roots and base sprouting telltale brackets of white fungus. A few have already crashed, and where the trunks and branches block the rides they are quickly cleared by men with chainsaws. The timber is good for little by that stage; it is probably burned.

In a quiet part of the spruce grove, a few yards from the nearest path, one of the trees, similar to its neighbours in every outward respect, has been singled out by a tawny owl. To the same broken stub of branch the bird comes time after time to rest and in peace and silence digest its meals. This December morning, in the half light of dawn, it is here again. Its great head turns; it blinks, makes a slight retching motion, and brings up a wet grey mass, a pellet of indigestible fur, bone, earthworm bristles, feathers, claws. The pellet tumbles eleven feet to the ground and comes to rest among a score of others of varying age.

Preserved in these capsules is the history of the owl's diet. If you know how to read them, the fragments of bone reveal much about the small mammals of the wood. Of course, the owl may have its personal likes and dislikes; it is not an impartial sampler. To get information of scientific value requires the dissection of many pellets from many owls over a great period of time, as was indeed done by one zoologist in a clever and original study. Taking these few home in a plastic bag, though, might tell us something, perhaps, that we do not already know.

With a lens and textbook the tiny bits of bone, cleaned now and dry, can be roughly sorted. Skulls in various stages of destruction, halves of lower jaws with or without teeth, assorted molars and incisors. Vole this side, shrew that. A wood mouse skull, or what's left of it. This lumpy-looking thing is a mole's humerus. A flat, fluted wishbone: the lower mandible of some dunnock-sized bird.

Among the shrew jaws there are two, both right-hand halves, which are obviously smaller than the rest. And here, in the as yet unsorted pile, is an upper skull barely half an inch in length. It once belonged to a pygmy shrew, the smallest of all our mammals. Handled like this, turned in stainless steel tweezers under a desk lamp, it seems impossible that a skull so small could once have held a mammal's brain or housed even such a quick, ferocious and hyperactive soul. Shrews do not live for long. Their existence is all aggression, greed, sex, a headlong madness to cram each minute full.

A year or two ago you found one drowned in the greyish fluid that had gathered in the bottom of a discarded preserving jar. The jar had been inside a sack of rubbish dumped in the ditch by a passing motorist. A fox, smelling chicken bones, perhaps, had torn the sack open and out had spilled the jar, coming to rest among the nettles. There it had lain, waiting for the shrew to find it and stumble inside.

That death was easy enough to understand; but what caused the end, last July, of the shrew you found dead in the middle of the path? The body was cool, but still limp. There was no sign of injury or any other cause of death. The nervous system, already running on maximum, may simply have conked out; or there could have been a failure in some vital valve of the perennially over-revved and overloaded heart. A pygmy shrew is miniaturization taken to extremes.

At that size nature is pushing the very limits of design, just as, at the other end of the scale, it is pushing the limits when the huge crown of a long dead spruce, yielding at last in the lifelong fight with gravity, splits off and falls with a thunder that makes the whole forest quake.

Ancient Aviators

The cormorants have chosen this lake, the biggest gravel pit in the Colne Valley, for their roosting place. There is a group of islands in the southern end that they have made their own. The birch trees there are sickly and dying, frosted with droppings. On these short winter afternoons, upwards of a hundred and twenty birds may be seen perching there, high and low, clustered in the trees like so many huge black fruits.

Today, for the first time all week, the sky is blue. Far off to the south and east, beyond Hillingdon and Ealing, the brown breath of London rises as smog; but northwards along the valley, beyond Rickmansworth and away to the west, the horizon looks comparatively clear. Here at Harefield there is as yet little of man in the atmosphere, except for the light planes constantly circling and landing at Denham aerodrome.

Since the wind comes generally from the west, the aeroplanes usually head straight across the valley and over the lake. They fly so low that you can see into the cockpits. Once over the main road, wings wavering somewhat if the pilot is a pupil, and with the undercarriage barely seeming to clear the trees, each one then drops abruptly and vanishes behind the ridge.

When they disappear like that you are half afraid, having seen too many cheap films, that after a short delay you will hear a low-budget explosion and see a low-budget pall of smoke. But no. Disaster is always held, once more, at bay.

No mechanics service the cormorants that use the lake. Neither do the birds bother with pilots' licences or subscriptions to the flying club. They have no need of manuals or airworthiness regulations. In flight they are perfect.

The style is basic rather than graceful, but beautiful nonetheless. It gets them very efficiently from one feeding area to the next, lets them escape from enemies, and allows them to perch and rest on any projection that takes their fancy.

The feet are broad and webbed; the dark skin and toes look rather clumsy wrapped round a stub of branch, but the bird appears quite comfortable and will remain there for a long time, perhaps with wings opened, slowly digesting its last gluttonous meal. The plumage is oily and dark, and the head has a peculiarly reptilian slant. It is easy to remember that the cormorant is a relatively primitive bird. _Archaeopteryx_ might have looked out on the world through such an eye as that.

The earliest specimen of the cormorant tribe yet found in Britain turned up in Hampshire, a fossil some fifty million years old. Even at that time the technical problems of making a cormorant fly had been completely solved, the complex equations of lift, thrust, and drag neatly dealt with and given tangible form in the bird's shape and plumage. The wingbeats that pass over the gravel works, over the pylons and the arterial road are the very same that passed over Eocene lakes and estuaries, over a Hampshire that would seem as strange to us today as the farthest corner of Brazil. In another fifty million years there will probably be similar-looking birds, perhaps even in this very spot, digesting fish and drying their wings on a planet where mankind and all its works are preserved, if at all, as fossils.

The cormorants care nothing for their illustrious ancestry. They care only about the next cropful of fish.

A bird at the end of the island planes down to the water. Swimming low, its back awash, it dives with a pouncing leap. Underwater, where we cannot see it, the most important form of locomotion is brought into play. The cormorant is said to pursue fish with the feet alone, without using the wings except occasionally as brakes. It can dive to a great depth, staying submerged for as long as seventy-one seconds, but prefers to surface to swallow its prey.

And there it is. It has come up a few yards farther out, clutching what looks like a roach. The head is tipped back; the jaws open, and down the fish goes. The neck bulges for a moment, and then, its appetite whetted, the cormorant dives for more.

Flaunden by Night

As the winter deepens the cold is becoming more intense. By midnight the puddles on the bridle-path are frozen almost solid and no longer break so easily underfoot. There has not yet been snow, but soon, perhaps, when the wind changes and cloud covers the sky, it will begin.

Meanwhile, nightly frosts are preparing the ground for it. Each morning the patterns on the windowpane take longer to disperse, and last night, the coldest yet, there was a loud report from the garden, like a pistol shot. The temperature had fallen so much that the sap in a high cedar bough had frozen, expanded, and split the wood.

The moon was out then too, the frost's accomplice, high and small and glaring white. The bluish-silver light it casts on the bridle-path is treacherous and not to be relied upon, but still you do not take the torch from your pocket, for your eyes are only now becoming adapted to the dark.

There is a childish excitement about an excursion like this, when sensible people are already warm in bed. You would be in bed now yourself, had you not suddenly decided to come out and see the sky.

Winter is a good time for stargazing. The nights are deep and the north wind drives impurities and heat haze away. The other bane of the amateur astronomer is the orange glow of sodium streetlamps, which extends for a surprising distance into the atmosphere. Out here, however, some distance from the nearest town, the sky is black to the horizon.

Emerging from the shelter of the hawthorns, the bridle-path runs beside a barbed wire fence and there, downhill across invisible fields, the whole of the southern sky opens out to view.

The patterns of stars, the constellations we speak of, bear little resemblance to the objects, creatures, or personages they are supposed to represent. In different ages and through different eyes the stars must have been arranged in many other ways, fitted to the legends and heroes of the time.

A few constellations, though, must always have been recognized in the shapes we know today. Cassiopeia is one, tonight an M rather than a W, hanging slantwise at a neck-stretching angle in the top of the sky.

Another is the giant figure that, eternally wheeling westwards, comes in winter to dominate the southern sky. Orion was surely always a hunter, a warrior. In our almagest he is locked in endless combat with Taurus, the bull. At his feet is Lepus, the hare. Orion's shoulders are made by Bellatrix and the red star Betelgeuse, and his rightmost ankle is the brilliant Rigel. His belt-buckle has Alnilam for a jewel; below hangs his sword, in which is visible, even to the unaided eye, the luminous cloud of the Great Nebula.

Near by, his two hounds are in attendance. The three stars of his belt point down to the larger, Canis Major, in which is the blazing blue-green cauldron of Sirius, the dog star, the brightest in the sky.

Sirius is so dazzling that it is difficult to see the lesser stars that immediately surround it. In the last century the astronomer Bessel noticed that Sirius seemed to be moving in a small orbit, and thought there must be a dark companion star. His idea was confirmed in 1862. Although the companion star is so much dimmer than Sirius, its surface temperature has been found to be about the same, and so, incredibly, the difference in brightness must be due to a difference in size.

The companion, Sirius B, is a white dwarf, in diameter an object only about three times the size of Earth. It contains as many atoms as our sun, but the spaces inside each atom have collapsed. Sirius B now has a density some fifty thousand times that of water, and just one teaspoon of it would weigh almost a ton.

The vast emptiness of Orion's limbs is almost like the emptiness of our own when compared with the stuff of Sirius B. Like the puddles in the bridle-path, like the cedar tree, like everything else on earth, we are made not so much of solid stuff as of vacancy.

Walking back, having spent a long time standing in the darkness and marvelling, you somehow feel no longer quite so insignificant or remote. The torch-beam is playing on the iron-hard ruts and ice; the basic laws of physics down here are just the same as those up there.

The wind is moving in the hawthorn branches. It has changed direction. Before dawn there will probably be cloud, low, dense, and tinged with yellow, and not long after that it will probably start to snow.

Secrets of the Goldeneye

Out there, towards the centre of the sheet, is a drake goldeneye, accompanied by three females. They are diving repeatedly, actively feeding. As he emerges the drake looks brilliant in the January sunshine, an essay in black and white.

Of all the species of wildfowl that come to spend the winter with us, the goldeneye is one of the most striking and distinctive. The plumage of the drake is not really black and white, but snowy white and the darkest glossy green or purple, depending on the angle of the sun.

At this range, though, the head looks black, with a large white spot below and just in front of the eye. This, and the elegant black and white pattern on the back and wings, lets you identify him at a great distance out on the water, even when your binoculars are being jostled by an east wind that numbs gloved fingers and makes the eyes stream.

The forehead of the goldeneye has a characteristically steep profile that enables you to pick out the females and immature birds – with drab grey bodies and chocolate brown heads – from the coots, pochards, and tufted ducks.

As would be expected, these drabber birds, or "morillons", usually outnumber the males. At its height in midwinter, the local population consists of no more than about a dozen birds, if that.

Looking back over twenty years of records on index cards, the assorted localities, numbers, and dates make for confusing reading. An evening with a pocket calculator and a tablet of graph paper is scarcely more enlightening. Statistical analysis, the calculation of means and probabilities and standard deviation, is time-consuming and prone to error.

But the naturalist now has a new ally: the microcomputer. Even a relatively humble model, obtainable in any high street, makes short work of the statistics. With a carefully designed program and carefully entered data, the real wizardry of the computer takes over and magic begins to emerge.

The records, hundreds of them laboriously culled over many notebooks and many winters, are transformed into a volatile set of electronic signals that the program manipulates at incredible speed. In a few moments we can abstract any given group of records – for locality, date, number, sex ratio – or put them back, or give them special weighting for greater observer coverage, or less. Touch a key and the graph illuminates the screen. Touch another and the figures appear.

January is shown to be the peak month for goldeneye in the Colne Valley between Rickmansworth and Uxbridge. Total birds and average record size both reach their maximum – except at Stocker's Lake, where there is a unique and unexpected fall. Why, and where do the birds go?

Press another few keys. Yes: that's where they go. A little way down the valley to the giant Broadwater gravel pit at Denham. The graph here shows a sudden and untypical rise in January. Press more keys. The rise at Broadwater corresponds almost exactly to the fall at Stocker's Lake. But why?

The answer probably has something to do with the goldeneyes' food: the molluscs and crustacea they find in the mud on the lake floor.

Either there is a preferred prey animal at Stocker's Lake that is harder for them to find in January, or some special delicacy at Broadwater that becomes numerous in that month. Or else it is a simple matter of ice cover. Broadwater, being so much bigger, will be slower to freeze and will do so less often. Already the computer is beginning to suggest lines of approach to the problem: it wants more data, on the weather, on water temperatures, on the goldeneyes' diet.

The machine reveals things previously known only to the goldeneyes themselves. Hidden deep in the figures are trends and patterns that a lifetime of casual observation would never uncover. They are real and constant from year to year, and must somehow be of service to the species in its struggle for survival. Similar, but slightly different, patterns emerge for closely related species. As the relationship grows more distant, so the patterns become more dissimilar. Goldeneye resembles teal, because both are ducks; but teal resembles mallard more, because teal and mallard are very near in evolutionary terms and have much the same way of life.

Here by the shore at Broadwater, despite your thick coat and woollens, you begin to shiver. The wind is dashing real waves, bigger than many at the seaside, against the crumbling soil of the bank. The goldeneye are impervious to the waves, impervious to the cold. Look – the drake has just surfaced.

How are his preferences and tastes programmed in the living chip behind that high, triangular forehead? And where in his memory are the myriad bits of navigational data that will guide him and his followers home in spring, a thousand miles and more to the rivers and forests of Russia and Scandinavia? Over what aeons of time was that machine code written?

A mystery. It's all a mystery. There: he has dived again.

At the Ford

It is hard to imagine that, only two months ago, during the August heat, we sat here dangling our toes in the water. The low planks of the footbridge over the ford were pale and dry then. A pair of swans and their three café-au-lait cygnets shared the river with us, hoping perhaps for a bit of bread, and rolling downstream, tumbling over and over itself, came a fist-sized mass of water starwort that caught for a moment against a bridge stanchion and then went on.

Now the swans have vanished, and so has the summer. After threatening all day, the clouds have finally darkened still more and brought rain. Coming down the hill, the storm could be seen as a grey haze cloaking the woods and fields of the next parish. It moved on to the village, enveloping the manor house and then the ancient stonework of the church. The gargoyles on the tower must have come to life almost at once, as did the yellow room-lights in some of the houses near the green.

The rain reached this spot a few minutes ago. There is no shelter to be had, only the wood, and to get there would mean a soaking. The best and only place is here, standing in the lee of an old and ivy-covered ash. The tree is at the top of the bank above the middle of the ford, overhanging the deepest water. There is not much dry space in which to wait out the rain, a few inches to stand in and no more. There is not even room to move the feet, not without risking a tumble into the ford. For as long as the rain lasts they will have to remain immobile, deprived of their freedom by the vagaries of the sky.

Any place takes on a different aspect when viewed not spontaneously, but from compulsion. This is especially so in the wet, and the effect is heightened when the field of view from your sheltering-place – be it a doorway, the arch of a bridge, or an ivy-covered ash – is restricted by the slant and direction of the rain.

The shelter of the tree extends for some way across the ford, spreading a broad tongue of smoothness across the surface of the river. From the edge of this area outwards, the momentary craters of the raindrops become bigger and deeper until they are just as big as those forming in the roadside puddles. Each one of the drops hitting the river has this last instant of individuality before being absorbed into the body of the stream. These drops have already begun their journey to the Thames and the sea; the others, landing in the puddles, in the fields, in the wood, pouring through the gargoyles, must wait their turn.

Their comrades, hordes of them, are at this moment swelling the water table below the river's source. The river rises as a threadlike brook, but grows quickly on its way here. In the grounds below a Victorian mansion a couple of miles upstream there is even a little cascade, provided with many small flaps to break the flow – either to make the sight more picturesque or to aerate the water for the benefit of the trout. A reclining stone god, a bit decayed, supervises from his central place on the lip of the falls, and there is just enough water going past to preserve his dignity.

From there the river continues to grow, winding through a damp, rich-soiled moor that is now mainly pasture. The water is very clean, and the wild plants in this stretch bring botanists on pilgrimages from London and elsewhere.

This weed coming downstream now, though, is one of the common ones. It too, like its predecessor on that August evening, is water starwort, but its green mass, gliding into the ford, does not head for the bridge but instead is brought by a quirk of current this way.

It comes close enough to see the shape of the delicate green leaves. Starwort from stagnant water often has leaves that are broad and round. Those on this specimen, however, are long and strap-shaped, which probably means it was dislodged from a fast-flowing section of the river. Half an hour ago, as the rain began, the weed might have flowed past the stone god and over his waterfall. Now, as the rain seems to be coming to an end, it drifts once more into the main current and disappears, watched by an immobile figure of quite another sort.

The worst of the rain has moved on. It's time to go. The sky to the west looks harmless enough. Secretly congratulating yourself on having kept dry, you climb down from the bank, cross the footbridge, and continue on your way.

Five minutes on, too far from your tree or any other shelter, your forecast is proved wrong. The rain sweeps in again, heavier than before; the dryness of your jacket, so carefully hoarded under the tree, is lost in an instant.

Nature is no respecter of dryness, or hoarders, and it may be that, as the water begins to trickle down your neck, the faintest of faint smiles is slowly forming on a certain stone face two miles upstream.

Up from the Pit

Here and there in this region on the edge of the Chilterns the soil consists of marl – a mixture of clay and calcium carbonate that was formerly used as fertilizer. The marl was dug with spades and wheelbarrows and hauled away on horse-drawn carts.

The abandoned pits can be encountered almost anywhere in the countryside. Most are fairly small, no more than fifty or sixty feet across and twenty or thirty deep. Sometimes they are used as tips for broken washing machines, rolls of rusty barbed wire, milk crates, and similar debris. Occasionally they are put to more ingenious use. The golf course green nearest the Iron Bridge in Cassiobury Park, for example, lies at the bottom of an old marl pit, the green itself thus hidden from the golfers on the tee.

In places that pit slopes pretty sharply; as children we used to toboggan there. Other depressions, a few as large, may be found near by in Whippendell Wood.

The marl was first dug at about the time, a couple of hundred years ago, when the grand landscapers were at work transforming the parks of the wealthy. This was also the heyday of the great furniture makers, whose factories at High Wycombe had an almost insatiable demand for hardwood. These factors combined to ensure the widespread planting of beech – a noble, imposing tree for planting schemes both formal and otherwise, and a valuable source of first class timber.

The grounds and park attached to Cassiobury House are now reduced to a fraction of their former size. In what remains – the present Cassiobury Park, the adjoining golf course, and especially in Whippendell Wood – evidence of this beech-planting can everywhere be seen.

For such a large tree the beech is not long-lived. After two centuries – a mere seventy or eighty thousand dawns – some of the planted specimens are piecemeal beginning to die. They are apt to shed a large bough without warning; it can be dangerous to linger too long underneath.

On the higher and sloping ground in particular the beeches have reached their best. In maturity they are massive, smooth-boled monsters with elephantine limbs and silvery-grey elephantine skin, sometimes bearing scars. A hundred pellet holes from a wanton shotgun blast, unleashed perhaps by a poacher who prowled the woods before any of us were born, have each expanded to the size of a ten-pence piece – or a florin, as he would have called it. The carved hearts and initials of forgotten lovers, expanding steadily with the years, have become indecipherable. One tableau has been so altered by the tree as to resemble the secret markings on some Druid stone, forming the face of a deity: the pagan protector of all things in the woods, not least of them the beech.

The beech nuts, or beech mast, are sometimes, as in this last autumn, shed in such prodigious quantities that they sound like rain in the days and weeks of their fall. They form an important source of winter food for many animals and birds; the population size of such species as great tit and chaffinch can be related directly to the abundance of the mast crop.

Each nut is quite small, half an inch long or so, of a pattern called by botanists "triquetrous", with three sharp-edged sides and a small rounded base. It opens at the tip in spring and there emerges a creamy white radicle that pushes down into the soil.

Competition among the seedlings is so intense that each has less than one chance in several hundred thousand of reaching maturity. The adult trees blot out the light, spreading a canopy a hundred feet or more overhead, and in the autumn send down a blizzard of leaves that, slightly toxic, inhibit undergrowth of any kind.

Only where a large tree has fallen, or where the ground has been otherwise cleared, do the saplings stand a chance. Then the race is on: the first up to the light is the winner, and the rest are left to die.

This may be seen plainly at one of the old marl pits in Whippendell Wood. Digging there must have been abandoned about a century ago and the soil left to its own devices. Surrounding the pit are veterans of the planting era; at the very edge are several whose roots have grown in a tangle down the slope. These trees are the parents of those that have sprung up in the pit itself.

The young beeches began with a handicap. Some have as much as thirty feet to make up before even reaching ground level. They have grown fast, with smooth, clean trunks, not wasting time or effort on producing limbs. Everything depends on reaching the canopy.

But the older trees have already taken the opportunity of spreading their branches further and further into the gap, greedily consuming the free space. Only one or two of the young beeches in the middle of the pit have any hope left. When existence itself is the prize, even these silent grey leviathans care nothing for their offspring.

The Red and the Grey

There was a dead squirrel in the road this morning. It had been run over, a broad, shallow trough left by the tyre across its back. From the look of its legs the squirrel had been stopped in mid dash; it had played the game of chicken once too often.

Such a game would be second nature to the grey squirrel. It has its own special brand of lunatic daring, leaping from branch to branch and tree to tree, sometimes across six feet or more of empty space. Occasionally it has to scrabble madly to stay on, or desperately abandon its grip and aim for another, safer, branch lower down.

And once in a while it makes a complete mess of things and misjudges altogether. Then there is nothing to do but go loose and, crashing earthwards through the twigs and branches, hope the ground isn't too hard below. One squirrel I saw fall hit the ground with a thump that made me wince, but the leaf litter was fairly thick and the animal, though a bit dazed, soon recovered and seemed none the worse.

They have a trick of keeping the tree trunk between you and them, slowly circling as you circle, coming back again, sometimes peeping out to see where you've got to. There is good reason for them to fear human beings, but dogs – which are never known to carry guns – are treated with impudence. Labradors in particular seem to get very excited when they see or smell a squirrel. The chase ends at a tree: the dog, barking loudly, tries to make itself taller, while the squirrel, having selected at leisure a comfortable fork some ten or fifteen feet up, sits back and virtually thumbs its nose.

The grey squirrel, even before the rabbit, is our most familiar mammal. It has adapted so well to the English countryside that one easily forgets that it, like the rabbit, is an introduced species. Whereas the rabbit was brought here by the Romans, though, the grey squirrel has only been with us since 1876, when four were brought from America and released in Cheshire. From then until 1929 there were fifty-two introductions at various places up and down the country, totalling a mere 247 animals in all. From these few the whole of our present stock is descended. By 1971 the grey squirrel was to be found in all but three of the counties of England and Wales.

It is a fairly safe bet that, wherever an introduced animal thrives, it turns out to be a pest. The grey squirrel is no exception. It has plainly found life here to its liking, and a glance at a government report on squirrels tells us why.

The staple diet of nuts, mainly acorns, hazelnuts, beechnuts, and chestnuts, is varied, in autumn, with the pick of the wild fungi, corn from the farmers' ricks and fields, and the choicest fruits, both wild and in the orchard. By Christmas, bulbs and buds are at their best. In February, swedes, parsnips and turnips are coming into season, and March sees the start of the freshly sown wheat and barley.

Squirrels may be practising vegetarians, but they are not faddists and will not refuse a meal of juicy insect larvae or pupae, or of birds' eggs or nestlings. In suburban gardens at least, so fond are they of eggs that they will gnaw through a heavy-gauge aluminium plate guarding the entrance hole of a wooden nestbox. The egg season, alas, is soon over, and by late June the squirrels must make do with strawberries, cherries, plums and, on into July and August, pears, peaches, and whatever they can find in the way of ripening wheat, oats, and barley.

The main fault held against the grey squirrel, though, is its taste for the sweet sap in the cambium layer of tree bark. Young trees between ten and forty years of age are most at risk, especially during the spring and early summer. The tree is usually scarred or distorted to some extent, and if the bark is gnawed off in a ring the tree will die. In some areas the damage is costly and severe.

Although the grey squirrel is popularly believed to have driven out the native red species, the truth is more complicated than that. It seems that the grey squirrel arrived at a time when the red was declining anyway – through disease, perhaps, and certainly through destruction of habitat. The two species will coexist peacefully for many years where they are found together, and in some places the red squirrels died out long before the grey ones arrived. Where grey squirrels are well established, however, they may prevent red squirrels from recolonizing. There is no question of the grey squirrels systematically killing the red, although it is certainly true that, on very rare occasions, individuals of the two species will fight, sometimes with fatal results for the smaller and lighter red squirrel.

The red squirrel is the more attractive animal, but if it had to go then the grey squirrel is an appealing enough replacement. Despite the most strenuous efforts at control, including a bounty scheme, the grey squirrel continues to thrive. If you are not a farmer or fruit-grower or forester, that will not seem such a bad thing after all.

Open All Hours

However hard the weather may be, the springs feeding the old watercress beds always continue to flow. They rise from a depth that is beyond reach of the frost, and on a cold day the water, which is limpid and sweet, feels almost warm to the touch. It flows across a mud and gravel bottom, making a stream that is here broad and there narrow, occasionally becoming louder as it drops an inch or two from one bed into the next.

Years ago, when these beds were worked commercially, the stream was controlled by a system of sluices and gates. Like the men who worked them, the sluices have gone now, rotted away, and the stream has to find its own passage through the sedges and willowherb. The cress then was eaten in local salads or decorated more expensive dishes in the West End; now it remains where it is, and makes an unpolluted home for a rich and abundant population of small aquatic invertebrates – worms, insect larvae, and the rest.

They are the set lunch for certain birds that may be found at cress beds more often than in most other places of the district. The beds here in the Gade Valley, as well as along the Colne and the Chess, form an important winter habitat for ducks and waders, and for wagtails and pipits – including the water pipit, once thought to be very rare but now known to be a regular visitor to watercress beds throughout the country. This discovery was made locally by a local bird-watcher to whom these abandoned ditches at Watford, between Bellmount Wood Avenue and the canal, are well known.

Quite often a few snipe are to be found here. If disturbed, they will fly up with a soft yet rasping cry, and pitch again after circling in a towering spiral that may take them two or three hundred yards further along the ditches. As might be expected of a gamebird, the snipe is extremely wary and unapproachable; but, if seen close to, it is revealed as a slender, thrush-sized bird beautifully camouflaged with brown and darker brown. The lower breast and vent are pure white; the legs are green; and the bill, which is inordinately long and equipped with a sensitive and slightly bulbous tip, is worked with a sewing-machine action in the mud.

The common snipe is usually silent as it feeds. Its smaller and scarcer relative, the jack snipe, however, progresses through the shallows with a series of inward and absent-minded grunts, as I once learned when I was lucky enough to observe one from a range of only six feet.

I was thirteen then, concealed in a cramped hide, made from bits of scrap wood and bundles of dry willowherb, which a like-minded school friend and I had constructed beside one of the ditches. From the same spot we watched most of the birds of the ditches in intimate detail. Besides the common sorts that came down to drink or bathe or look for insects, and besides the moorhens that may be found by almost any scrap of water, there were water rails – like smaller, drabber moorhens with a longer bill – and during several memorable dusks, up to four even smaller and drabber rails called spotted crakes – unusual birds indeed.

At that time there were three ditches, instead of the one that remains. They were separated by a tangle of reeds and scrub that held breeding pheasants, whitethroats, and sedge warblers, and in winter a large pied wagtail roost. From November to March the ditches would often produce a green sandpiper or two, besides other, scarcer, waders, a good number of mallard, and ten or twenty teal.

All that has now gone, buried under the sterile expanse of some rugby pitches that hardly ever seem to be used. Too late the site was declared a nature reserve; the bulldozers have driven the best of the birds elsewhere.

A few of them may be found a mile or two downstream, at the cress beds lying between the canal and Cassio Lake. A public footpath runs along one end, beside a rickety corrugated iron fence that helps to conceal your presence.

Here, if you are quiet and prepared to wait, you have a very good chance of seeing kingfishers, herons, water rails, snipe, grey wagtails and, a speciality of these beds, teal. During the recent cold snap there were upwards of fifty teal feeding busily among the cress near the fence, giving marvellous views.

They had homed in from icebound ponds and streams up and down the valley and beyond. Like the snipe, the moorhens and mallard, and all the other birds, they rely on the warmth of the springs for their emergency supplies of food. The cress beds, at least, always remain open for customers, no matter how low the mercury falls.

Bird Song

Unless you are lucky enough to have a knowledgeable friend with the patience to teach you, learning to identify birds' songs and calls can be a difficult business. There are records and cassettes available, and these are certainly a help, but there is no substitute for learning from nature.

It is well worth the trouble. Most experienced ornithologists use their ears just as much as their eyes and, once learned, the different birds' voices are found to be quite distinctive after all.

Early in a new year is an excellent time to start. At present, very few species are in song, and those that are can be identified with ease. As the year advances, other species begin to sing and can be learned one by one, well before the arrival of the summer visitors. Once the voices of the resident, native birds are known, it becomes much easier to learn the songs and calls of the summer birds that make a May hedgerow such a confusing place for the would-be ornithologist.

If you have a garden or just live within earshot of singing birds, or if you regularly walk the same route to school or work, the problem is simplified still more.

Take a sheet of foolscap or A4 paper and divide it into 15 or so columns and as many rows as you conveniently can (squared paper is ideal for this). Each row represents a day; in each of the columns, write the name of a bird as you identify it or as it comes into song.

Keep your chart and a pencil in a handy place, and each evening make a mark in the columns of those species that you have heard singing during the day. This exercise, if carried through, will have the effect of making you listen and differentiate every single day, so that learning becomes as effortless as possible. You will also end up with a scientific record of the way that the number of species singing gradually increases as the summer approaches.

The first candidate for a column is likely to be the starling, which sings virtually throughout the whole year. Its song is often delivered from a chimneypot or bare twig at roof height, and consists of an unmusical collection of wheezes, rattles, and whistles, incorporating a number of sound-effects and impressions of other birds. The starlings near our house do a very passable curlew, quite a good coot, and a fair lapwing impersonation. According to one newspaper report, an amateur football match once had to be called off because of a starling that insisted on copying the sound of the referee's whistle.

Another bird in song throughout December and January is the dunnock, or hedge sparrow, a modest, inoffensive little creature, brown above and grey below, which moves about the edges of the lawn with shuffling movements of its wings. The song is a pleasant warbling, rather subdued, of no great duration or power, slightly discordant, repeated at short and irregular intervals. It is usually given from a shrub or low bush; the main call-note, worth learning because the bird spends so much time hidden, is a piercing _tseep_.

The starling and the dunnock sing almost continuously during January, whatever the temperature. On milder days they will be joined by the robin, song thrush, and perhaps wood pigeon.

In winter, both male and female robins maintain an independent feeding territory, and both sexes sing. This winter song is often described as thinner and more wistful than the males' spring song: it is made up of short warbling phrases, slightly shrill. Sometimes, if the weather is specially mild, a robin can be heard in January and February at night. The alarm call is a distinctive _tic, tic_ ; other calls are a plaintive _tsee, tsit_ , and variants.

The song thrush is one of the virtuosi of the garden. Its song is clear and musical, consisting of a succession of short phrases. Each phrase may be repeated several times, and it is this repetition that is so typical of the song thrush. Some thrushes are more accomplished singers than others, and day after day can be heard going through and refining a repertoire that can include half a dozen favourite phrases. The alarm call is a sudden _tchik-tchik-tchik_. A note often given in flight is _sipp_ , and the distress call is a penetrating _seee_.

The most beautiful song of all comes from the blackbird, which does not start to sing regularly until the end of February. The blackbird's voice is richer and more mellow than that of the thrush. The song is more sustained; there is no straight repetition, but an endless improvisation and exploration of a number of themes. It has been found that individual blackbirds vary a great deal in their talent. The song of young birds is rather uninspired, but an older and more experienced male can give a truly musical performance. Such a bird will sing even though there is no need to guard the territory, and on such occasions it is hard not to believe that one is listening to a real aesthetic sensibility at work.

The blackbird's alarm call is a characteristic loud chatter. A note of milder alarm is _chook_ ; and at dusk, just before going to roost, the neighbourhood blackbirds engage in a communal chorus of _chik-chik-chik-chikk_ ing.

The only songbird that might be confused with the song thrush or blackbird is their larger relative, the mistle thrush, which is less common and is generally found in wilder countryside. It begins to sing regularly from the second week of February. The song is loud, relatively unmusical, with an aggressive quality, consisting of a series of short phrases delivered from the topmost branches of a tree. The alarm note is a harsh churring rattle.

Other birds to listen out for, in order, are the collared dove; the wren, whose song is astonishingly loud for the size of the bird; the chaffinch, greenfinch, blue tit, great tit and, if you have large old conifers near by, coal tit and goldcrest.

By the time March comes round and with it the first chiffchaff, you should be in a good position to learn the voices of the summer birds. The greatest challenge to your skill will be the dawn chorus in mixed woodland, but, until then, good listening!

White's "Selborne"

Gone now, like most of the town's character, is the old second-hand bookshop in Queen's Road.

The shelves extended from floor to ceiling and were crammed with volumes in all conditions and on all subjects. Ecclesiastical titles abounded, as well as Victorian novels with an improving moral tone – evidently the fallout from yet another broken-up rectory library.

These were of no interest to me. At the age of thirteen, the corner I liked best was devoted to books on natural history.

As with gold prospecting, a lot of spoil had to be sifted before you struck a nugget, especially since many of the book-spines were illegible. But nuggets there were, overlooked by the less persistent (and no doubt more affluent) customers.

One of my best buys, for the princely sum of 2/- (10p), was a book bound in embossed green cloth and decorated with gilt, undated, but evidently published about 1869. "Arranged for Young Persons", and liberally illustrated with steel-engravings, this was my first sight of that most delightful and enduring classic, Gilbert White's _Natural History of Selborne_.

While not going so far as one author, who declared that no one who does not own and appreciate a copy of White's _Selborne_ has no claim to call himself an English naturalist, I would nonetheless hold it up as indispensable to the library of anyone who loves our countryside, or who loves our language properly used, or both. As a Christmas gift, especially for a "Young Person" with an interest in natural history, it could hardly be bettered. There have been nearly three hundred editions; the book is never out of print.

Gilbert White was born in July 1720 at Selborne, Hampshire, where his grandfather was vicar of St Mary's church. Educated at Basingstoke and then Oriel College, Oxford, of which he became a Fellow in 1744, he was ordained in 1747. Although later given a college living at Moreton Pinkney in Northamptonshire, White chose not to live there, but installed a curate, preferring to remain, a curate himself, in his beloved native parish.

His house in Selborne, The Wakes, stands almost opposite the village green and today has been made into a museum. It was the garden at The Wakes, much improved by White and his father, that gave rise to some of his earliest writings on nature, kept in a journal called the _Garden Kalendar_. The garden features often in the pages of his _Selborne_ , and lends the book its core of parochial stability and charm.

White was happiest in the country, content to leave the city to his brother Benjamin, who became a prominent bookseller and publisher, handling many of the most important natural history titles of the day. Through Benjamin, Gilbert was introduced to leading naturalists such as Thomas Pennant and the Honourable Daines Barrington.

_The Natural History of Selborne_ consists of White's edited letters to these two men, written over a period of some twenty years. The first series of letters is addressed to Pennant, a famous, professional zoologist; Barrington was an amateur, an antiquary as well as a naturalist. White's great gift was that of combining careful personal observation with a transparent and graceful literary style. Each paragraph rings true because it is a distillation of what he has actually discovered at first hand.

The two series of letters reflect the personality of their recipients. With Pennant, White is rather formal and scientific. The letters to Barrington tend to be longer, more gently humorous, and more filled with human detail.

He writes to Pennant: "On a retrospect, I observe that my long letter carries with it a quaint and magisterial air, and is sententious; but when I recollect that you requested stricture and anecdote, I hope you will pardon the didactic manner for the sake of the information it may happen to contain."

White is never didactic, or magisterial, and some of the information his letters happen to contain is of historic importance to European natural history. He was fascinated by animal behaviour at a time when most zoology consisted merely of collecting and naming specimens; his discoveries include the differences between the leaf-warblers, between the common and lesser whitethroat, the presence in England of the noctule bat and, perhaps most famous of all, the harvest mouse.

"I have procured some of the mice mentioned in my former letters, which I have preserved in brandy," he writes to Pennant in November, 1767. "From the colour, shape, size, and manner of nesting, I make no doubt but that the species is nondescript ... They never enter into houses; are carried into ricks and barns with the sheaves; abound in harvest; and build their nests amidst the straws of the corn above the ground, and sometimes in thistles ...

"One of these nests I procured this autumn, most artificially plaited, and composed of the blades of wheat; perfectly round, and about the size of a cricket-ball; with the aperture so ingeniously closed, that there was no discovering to what part it belonged ... This wonderful procreant cradle, an elegant instance of the efforts of instinct, was found in a wheat-field, suspended in the head of a thistle."

His inquiries covered the whole sphere of the natural world, from birds and flowers to geology and the weather. He had a special interest in bird migration. At that time it was believed by some people that swallows, for example, remained here for the winter, lying torpid in the mud at the bottom of ponds. White, who inclined to the correct view, added greatly to the debate.

He was intrigued too by nature's oddities, and had a soft spot for his aunt's old tortoise, Timothy (not least because its habit of hibernation might throw some light on the migration controversy). On the death of his aunt, White brought the tortoise by post-chaise to Selborne: the shell is now on display in the Natural History Museum at Kensington.

White's legacy is the conviction that anyone, equipped only with a keen pair of eyes and an open mind, can add information of real value to our knowledge of the world. He has been an inspiration to countless people since, including some of today's most eminent scientists. His era, like the bookshop in Queen's Road, may have passed into history, but the spirit he embodied lives on.

Staines Reservoir

It would be hard to find a worse example of urban blight than the area round Heathrow airport. The country there, twenty miles south of Watford, where the Colne meets the broad valley of the Thames, was once, long ago, a place of rushes and placid water, of willows and marsh. But the Thames gave birth to London, and London grew.

The river plain makes an ideal site for one of the world's busiest airports. An airport of course brings development of the road system, which in turn brings factories. Besides this, the valley floor is replete with gravel for the construction industry.

We see today the result of all that. The area has been devastated. Everywhere the eye falls there is ugliness: pylons, motorways, industrial estates, concrete hotels, scrap yards. The very landscape seems to be in continual turmoil, ceaselessly being bulldozed and reshaped. Once every two or three minutes an airliner leaves and another one arrives, and even with today's quieter jets the noise is inhuman, intolerable. The people who live there must shelter behind double or triple glazing, and some shelter behind tranquillizers.

What is very surprising to learn is that this district is one of the best in England to see birds. The birds care nothing about aesthetics. Their main concern is food. Once, at the Perry Oaks sewage farm beside the airport, I saw a party of waders happily feeding while a Boeing 707 tested its jets on an adjacent runway. The noise was so horrendous that I had the alarming experience of feeling my whole diaphragm, my ribs and chest, beginning to vibrate.

The sewage farm is destined to be buried under a new terminal and, ever since terrorists threatened to shoot down an airliner at Heathrow with a surface-to-air missile, members of the public are no longer allowed there.

But, if the sewage farm is no longer accessible, there are other places that are. A little way to the south, just by Stanwell Village, lies one of the most famous birding sites in the country, Staines Reservoir.

When it was completed in 1902, Staines must have been seen as a wonder of modern engineering. Its surface area of 424 acres is divided in two by a ruler-straight causeway, 1100 yards long, aligned from east to west. The reservoir is so large that it has its own miniature tides; the water is hardly ever still, and even a light breeze drives it into waves that break against the concrete slabs of the leeward side.

The fame of Staines Reservoir began with a series of papers in _The Zoologist_ for 1906 and 1908, written by G W Kerr, who reported seeing as many as 80 great crested grebes there – quite an event at that period.

In Edwardian times bird-watchers were few and far between: regular observations at Staines were resumed only in the early 1920s, by such stalwarts as W E Glegg and A Holte Macpherson, who established Staines's reputation as a major site for wintering waterfowl. The recognition of reservoirs as unofficial bird sanctuaries began with their work and has now spread all over the world.

The sheer size of waters such as Staines allows wildfowl to rest undisturbed during the day. At night many of the ducks find feeding elsewhere along the valleys of the Thames and Colne – on the rivers, gravel pits, wet grazing, and streams of Middlesex, Berkshire and Surrey.

But the reservoir itself also provides valuable feeding opportunities. Unlike, say, the upland lakes of Cumbria which are often pretty barren of life, the reservoirs drain from the fertile valley of a lowland river. The water is rich in plant nutrients and, taken directly from the Thames, already contains a wealth of seeds, plant fragments, and small animals like annelid worms, insect larvae, and molluscs.

Except at the margins, though, the water at Staines is too deep to provide much for those ducks, like the tufted duck and pochard, which get their food from the bottom, or those, like the mallard and teal, which dabble in shallow water. These birds use Staines mainly as a resting place, often in large numbers. Flocks of 500 tufted duck and 300 pochard are not unusual in winter.

The species favoured are those that chase and catch fish, and Staines is an excellent place to see those scarce and beautiful winter visitors, the sawbills. The name comes from the serrations on the bill, which enable a firm grip on the prey. Largest is the goosander, the drake predominantly cream with a bottle-green head and red bill, the duck grey with a brown head and white throat. Upwards of 20 are regularly seen here.

As the winter deepens the tiny smew come in. The male is a pure, startling white, marked with elegant pencillings; his consort is, like the duck goosander, grey in the body with a white and chestnut head.

Red-breasted mergansers also occur, as well as even rarer species like long-tailed duck and scaup. And Staines is a favourite site for the scarcer grebes, especially black-necked. On one afternoon in January no fewer than four species of grebe were present: great crested, red-necked, black-necked, Slavonian.

Whenever one side of the reservoir is drained for maintenance, an expanse of mud and pools results that brings not only large flocks of teal and mallard, but waders, some of them extremely rare, including, in recent years, a number of American vagrants. Besides snipe, lapwing, redshank, dunlin and ringed plover, the drained bed often holds, in season, ruff, greenshank, little stint, grey and golden plover, godwits, little ringed plover, and spotted redshank.

If you have a warm coat and gloves and don't mind the wind, there can be few more exciting bird-watching outings than a winter visit to Staines Reservoir. From Watford, take the M25 to the Heathrow turnoff and turn south along the A3044 towards Staines. At the traffic lights turn left along the B378, and follow this road round into Stanwell Village, turning right at the pub on the corner. Keep on the B378 for another 0.6 miles; the gate leading to the path up the embankment will be on your right (OS reference TQ 056732).

A Moorhen

The spring equinox is only a month away. During the past week or so, the sun has been trying out its strength as if in rehearsal for the season to come. Between showers and periods of cloud, it has lit up the hills and pastures and sent experimental patterns of reflection up into the old willows by the canal.

During these warm interludes the seesaw song of the great tits can be heard most loudly; the rugged bark of the willows seems almost to expand in gratitude. Fraction by fraction the puddles on the towpath are shrinking. The river is no longer so full. The wind is being given a chance to do its work and, on balance, the countryside is beginning to dry out. Winter, with all its rigours and privations, is nearly over at last.

There have been many casualties among the small and weak, and especially among those animals that are deprived of their food by ice. Quite early on in the snowy weather the kingfishers went elsewhere. Some have perished. The water rails also fared badly, but their larger relatives, the moorhens, for the most part stayed and stuck it out.

Even in one horizontal blizzard, when the sheer density of driving snow obscured the wood on the hill, the moorhens were to be seen among the stubbles, searching for whatever they could find to keep themselves alive. They endured night after night of freezing fog, sleet, granite-hard frost. They survived the attentions of foxes that were themselves driven to desperation by hunger and cold. Each morning the moorhens' tracks – large, backwards-pointing arrows in the snow – could be seen crossing and recrossing the riverbank and the towpath and the lawns adjoining the water.

Now all that is forgotten. What lies ahead is spring, summer, the breeding season, the time of plenty. In April and May there will be the satisfaction and damp warmth of a deep nest filled with eggs, hidden somewhere safe and silent among the flags. Afterwards there will be the chicks, like small black powder puffs with beaks, frantically swimming behind their parents and trying to keep up.

There is one moorhen, though, which, if you are not careful, will not even live to see tomorrow, still less the breeding season. It is caught up in the middle of a thorn bush beside the towpath. Had a slight fluttering of dark feathers not attracted your attention you would have gone breezing past.

The thorns are sharp and tear at your wrist where it is not protected by the glove. The moorhen thinks you are going to kill it. Terrified, it tries in vain to burrow more deeply into the tangle of branches, but its movements are hampered anyway; a few moments more and you make contact. Holding the bird as gently as you can, and moving branches aside with your free hand, you slowly and carefully begin to bring it out.

Your fears are confirmed as the moorhen comes free of the thorns and you are able to examine it more closely. The wings and legs have been snared by several yards of discarded fishing line. The bird's struggling attempts to get free have made matters worse: the thin, translucent filament is wound into an inextricable maze of knots and tight loops, some so tight that the flesh on the upper legs has been deeply cut. Each movement of the bird tends to widen the wounds.

The moorhen makes no sound. Its beak is slightly open and its small, button-like eye seems no longer to register fear, but resignation. It is waiting to be dispatched, in accordance with the law. Big eats small. That it understands. But it cannot understand why or how it became ensnared. Nothing in its ancestry or experience has prepared it for nylon line.

Using fingernails alone, you would never be able to get the knots undone. They are simply too tight, too small, and too complicated. A penknife would not help; even a fine pair of scissors would be too clumsy. Luckily, since having seen a dead thrush trussed in this stuff and dangling from a tree, you now always carry a very thin, sickle-shaped scalpel blade. It is brand new, and gleams through a smear of grease as you take it from its cardboard sleeve.

Sharp as the blade is, the job is difficult and takes a long time. The moorhen slowly becomes more placid, sensing perhaps that it is not to be killed after all. One wing comes free, and then the other. Being especially careful, cutting one strand at a time, you free the legs. At last the final bit of filament is removed.

Unnoticed, the sun has gone in again. Nonetheless there can be no doubt about it: spring is on the way, and for the moorhen now as well.

Its wounds will heal quite quickly. Birds are hardy and resistant; there are no fears on that score. It is already able to walk unaided. As you stand clear, it slightly stretches its wings. After a moment's further trial, the moorhen launches itself and takes off and, legs dangling, flies across the ditch, beyond the nettles, and disappears from view.

Frogs

Just about now, as the sun grows stronger and the soil grows warmer, the frogs are coming out of hibernation. They have spent the winter in a state of torpor, hidden in mud at the bottom of ponds and ditches, or in compost heaps and other damp places.

Frogs are cold-blooded. When the temperature falls their vitality is lowered. Although they have lungs, they also breathe through their skins – provided they can be kept damp – and the small amount of oxygen they absorb in hibernation is enough to keep them ticking over.

During the long winter months, gradual changes have been taking place in their body chemistry. Hormones have been at work. On awakening in the spring, the frogs are immediately ready to breed.

The males have developed a large, swollen pad on the ball of each "thumb". With this the male grips the unfortunate female in a cold, clammy and muscular embrace that may last for days on end. In their frenzy to mate the males are none too choosy; they have even been known to grapple a good-sized goldfish, and clumps of half a dozen frogs or more can form that would even make the author of the _Kama Sutra_ blush.

The males cling on, waiting for the females to exude the streams of spawn, which are fertilized as they emerge. A slimy coating on the eggs swells almost immediately on contact with water, so that the spawn floats close to the surface, close to light and warmth.

A fortnight later the tadpoles begin to hatch. At first they resemble the fry of tiny fish, minute black slivers clinging in clusters to fronds of weed. Within a few days the mouth is fully developed and they start to forage on minute algae and other vegetable matter. They breathe using two pairs of feathery gills, external at first but later internal. The tail grows longer, and the body fatter.

Then, a few weeks after hatching, two buds appear that develop into hind limbs; the body becomes flatter and the eyes migrate to the top of the head. Next the forelimbs emerge. At this stage the lungs are already well developed and the gills, like the remains of the tail, are absorbed. The metamorphosis from larva to adult is complete. Three months after hatching, the tadpoles have become froglets.

The casualty rate among spawn and tadpoles is high. Besides fish, their enemies include many sorts of insects. Among the most ferocious of these are dragonfly nymphs, sometimes called the "Tigers of the Pond", and the even more ferocious and aggressive backswimmers, bugs with the scientific name _Notonecta_.

By the time the young frogs leave the water and are ready to start exploring the damp vegetation near by, their chances have improved somewhat, but they are still at risk, although from a different set of enemies. A number of water birds – including herons and ducks – are partial to frogs, and so are brown rats, foxes, and water shrews.

For defence the frogs rely on their powerful hind legs, with which they can spring out of danger, and on the cryptic colouring of their skin. The spots and blotches help to break up the shape of the frog and make it harder to see, and the colours themselves – green and brown and dull yellow – blend in well with the background.

In addition the frog can change colour to some extent, like a chameleon. There are special cells in the skin containing dark pigment. In dark, wet, or cold conditions the cells expand, making the frog look darker; in hot, dry conditions they contract and the frog can appear almost sand-coloured.

Adult frogs have two modes of feeding, both quite effective in their way. The upper jaw, but not the lower, is equipped with a set of backwards-pointing teeth. The prey – mainly worms, slugs, and large insects – is seized and held with the jaws and then swallowed whole.

The other mode of feeding is more colourful and makes use of the frog's excellent eyesight. Glands in the roof of the mouth exude a sticky goo; the tongue is long and forked and rolled back on itself when at rest. Should a suitable insect alight near by, or even cruise past, the tongue is uncoiled at lightning speed, brushes past the glands, and the insect is glued to the tip, whereupon it is brought back to the mouth and swallowed with a complacent blink of those big, bulbous eyes.

Frogs have set migration routes and a sort of inbuilt memory of ancestral breeding grounds, returning year after year to the same spot, even when the pond or ditch has long since been filled in. They have suffered badly in this district from the activities of man, and tadpoles should never be kept in jamjars: much better to leave them in the wild.

For all their promiscuity at breeding time, frogs are to be welcomed in the garden, as they destroy vast numbers of slugs; and anyway, March would not be March without their quiet, lascivious croakings, the plop as they dive into the goldfish pond, or the tapioca-like masses of spawn that signal the start of another spring and another summer.

Wind

Two thousand miles away, in the weather cauldron of the Atlantic, air swells above the surface of the ocean and the pressure rises. The Arctic pack ice will soon be breaking up: spring is coming to the northern hemisphere. Powered by the sun, vast changes are at work in the patterns of the sky.

The brunt of the sea wind is taken by the rocky western coast. By the time it reaches this far inland, on the field edge by a small Hertfordshire wood, it has only enough strength, at first, to move the leafless twigs and branches of the trees. The sound it makes in the canopy is gentle and sweet, but insistent, the token of stronger wind to come. Where the sky is clear, it is unusually blue, and the clouds are white, making huge, luminous mountains and ravines. Their terrestrial shadows must struggle to keep up, lumbering westwards, towards London.

By fits and starts the wind grows in strength all day. Down here in the dry valley, the buffets are absorbed one at a time by the wood. Trees moderate all extremes, of wind, of heat and cold and rainfall, and for the moment they are still in full control.

But the wood is only a remnant of what once was, and an artificial one at that, allowed to stand for the sake of the breeding pheasants. From most of this landscape the forest was stripped long ago, and now even the hedgerows are going, leaving flinty pastures divided by barbed wire, and nothing to challenge the late winter winds on their long sweep in from the west.

Up at the farm, on an exposed hillside, the wind is already a force to be reckoned with. The fence wires are taut and moaning, and the cattle have moved nearer the farm buildings.

The energy of the wind, if only we could convert it efficiently, would put a nuclear power station to shame. It appears to us to be squandered, thrown away, but in the natural world nothing is ever wasted, not even the wind.

In the landscape that was, the winter gales cleansed and purified the forest, weeding out dry branches, bringing down old and sickly trees so that saplings were given a chance. The spaces formed in the canopy allowed light to reach the forest floor, encouraging a rich variety of plants that lasted as long as the clearing did. The fallen timber itself gave opportunities to a wide range of specialist insects, mosses, lichens, ferns and fungi, and to all the creatures that fed on them in turn.

The wind not only causes the final crash of dying trees: it is also the chief agent of decay, spreading, by the hundreds of thousands of billions, the spores of timber-rotting fungi, so that no broken branch or wound in the bark is anywhere safe from infection.

Besides death, the wind broadcasts life. Migrating birds make use of favourable winds; all manner of seeds, from thistledown to the spinning blades of ash and maple seed, are dispersed on the air; and if a flower does not have nectar or a showy set of petals, it is probably pollinated by the wind rather than by insects or other animals.

Like the fungi with their spores, wind-fertilized plants produce their pollen in staggering quantities. In summer no part of the atmosphere is free of grass pollen, and even well away from the hayfields the levels can be high, as allergy sufferers know to their cost.

Grasses are highly evolved plants, and their flowers show a reduction and simplification of structure that is shared by most wind-pollinated flowers. Quite often the female stigma is feathery or sticky, or both, to give it more chance of catching pollen, and quite often the flowers, instead of having both male and female parts in the same structure, are of separate sexes. The male plants then usually outnumber the females, and cover large areas of ground.

Among those sorts that must coexist with broad-leaved trees, flowering comes early. The hazel catkins appear in the first fortnight of February; a little later come the small grey mice of the sallow flowers, and this week, at the wood, the dog's mercury is coming into its own – a plain, simple-looking plant, related to the spurges and more distantly to the nettles, which is a classic of wind pollination. With each gust its pollen can be seen drifting in faint yellow clouds. The female plants grow in clumps surrounded by carpets of males, so that whichever way the wind blows they are sure to be pollinated.

The sight and smell of dog's mercury pollen always come with the March wind. So too does a special transparency of air, a clarity and subtlety of colour. Up here, there is nothing to obstruct the vision. The range for the eyesight goes on and on, away towards Bovingdon, towards Aylesbury, away past the horizon, and beyond, to the incoming cloud mass and the pure, wild air above the sea.

The First Chiffchaff

From the wintry thicket of sallows across the river come two silvery notes, in colour like the March sunshine itself, repeated several times in succession, rising and falling in an irregular and unpredictable cadence. The sound, noticed just a moment ago, brings with it a surging feeling of freedom and release, as if a long and tedious series of obstacles had finally been overcome. The first chiffchaff has arrived, so it must be true: spring is here, and that really means that winter has gone at last.

Presently you manage to glimpse the bird, a small, slight warbler with dark legs and a faint eyestripe, the plumage dusky olive above and lighter below. It is flitting about in the branches near the water, tirelessly searching for small spiders and insects, which it takes with a deftness and delicacy almost too quick for the eye to follow.

The song is abandoned; the chiffchaff has become more absorbed in its feeding, and flits now to an elder bush whose oily, dark-green leaves are already well out. The bush holds no interest, and the chiffchaff moves on a few yards to the north, to the red-stemmed dogwood thicket, where it again begins to sing. _Chiff-chaff, chiff-chaff, chaff-chiff, chiff-chaff._

But "chiff-chaff" is too harsh a way to represent the song. The Germans call the bird "Zilpzalp", pronounced "tsilptsalp", which comes a bit nearer the truth, though the notes, like nearly all bird sounds, are impossible to render accurately in any human scheme of phonetics. Later in the spring the song will be heard away from the river, in woods and wooded scrub, well-timbered parkland and gardens, but the earliest arrivals nearly always appear by water.

Although one or two chiffchaffs frequently spend the winter along this stretch of the Colne, this bird, with its song and the way it is progressing from bush to bush northwards, is almost certainly a migrant.

The chiffchaff is usually the first in the annual tally of our local summer visitors. A day or so later comes the wheatear – scarcely to be found in this district now, unless sometimes on the broad arable fields above West Hyde; next, the willow warbler, outwardly almost identical to the chiffchaff but with a completely different song; next, the sand martin, tree pipit, and yellow wagtail; and then, in quick succession, the swallow, blackcap, house martin, and all the rest, ending with the turtle dove, normally the last of the common migrants to arrive, in the latter days of April or the first of May.

Most of these birds winter in Africa, some as far south as the Cape. How they manage to navigate is still not properly understood. Some species, the blackcap, for example, have been shown definitely to take their bearings from the stars. All can steer by the sun and have the acute sense of time that this necessitates.

It is believed by some scientists that certain species have an inbuilt compass sensitive to the earth's magnetic field, though no one has yet found any tissues that might perform such a function. A compass would certainly explain some of the more spectacular feats of bird navigation, in fog or on cloudy nights; but then, these are the very conditions most likely to confuse and disorientate most migrants.

Leaving aside the technical difficulties of navigation, the main problem for migrants is the sheer expenditure of energy needed to complete the journey. Larger birds, such as eagles and storks, which have wide, high-efficiency wings, are able to climb to altitudes where they can take advantage of the wind. Small ones, though, like the chiffchaff, tend to progress yard by yard on the ground, and this method of travelling is called "bush-to-bush" migration.

Set against all the difficulties and dangers of migration, the advantages to the species are very great. It is able to breed in latitudes which, uninhabitable in winter, have immensely long summer days compared with those nearer the equator. At midsummer in England there can be as many as eighteen hours of daylight in which to find food for the young. This enables more and larger broods to be raised, and the increase in breeding success must outweigh the losses of adult and immature birds on the spring and autumn migrations.

Our chiffchaff this morning has probably wintered no further away than the Mediterranean. Nonetheless it has had to cross the whole of Europe and, worst of all for such a small land-bird, the English Channel. Having made land on the Hampshire, Sussex or Kent coast, it has moved steadily northwards, following wherever possible the river valleys, which are both sheltered and provide the most abundant supply of early insects.

Yesterday or the day before, some combination of landmarks in the broad valley of the Thames near Staines directed it northwards along the Colne. Twenty miles later it appeared here.

Now it has passed on, several hundred yards upstream. The urge to move north and breed is irresistible, of a pattern with the daily increase in the power of the sun.

Having been silent for a while, the bird is heard singing once more, faintly, a new arrival at some fresher and more northerly stretch of the river.

Hares

April is still ten days away, but out there, across the broad expanse of dark-brown furrows, the air is already shimmering with heat. Seen from this low angle, from this quiet vantage place beside the hawthorn hedge, the heat haze seems concentrated and condensed; the white geodesic dome of the Chenies weather-radar looks misshapen and wobbling on the shaky substance of its tower.

The air is filled with the song of many skylarks, and from the asterisked lines of barbed wire by the bridle-path come, over and over again, the same jangled notes of a corn bunting. A thrush is singing, and just now a woodpecker drummed from the direction of Baldwin's Wood, but otherwise the place seems devoid of life. The fields here are too open, the hedgerows too sparse. The arable is a desert, a harsh and unpromising place for wild creatures.

Earlier this morning, though, when the sky was still grey with dawn and the light was only just good enough for the human eye to perceive detail, these same furrows were the scene of a prolonged and spectacular contest. Two buck hares, mad March hares, were fighting, either for territory, or for possession of a doe that remained unseen and, more than likely, indifferent to the outcome.

The contest, or ritual, was enacted as a chase in which the two hares displayed to the full their agility and powers of running, dashing across the clods, the subordinate animal doing most of the giving way. Occasionally, however, it mastered its timidity and stood its ground, rearing up on hind legs at the approach of its antagonist. Often as not it would think better of this tactic and again resume running, but once or twice it held firm and a few rather ineffectual sideswipes were exchanged.

These boxing matches are seldom seen nowadays. Changes in land use and farming methods have made the hare very scarce. Once it was a common animal, a feature of all landscapes such as this. It was included in the traditional list of the five beasts of the chase – the Hart, Hind, Hare, Boar, and Wolf – and occupied an important place in the tradition and lore of the countryside.

Nevertheless, for such a large animal (it can weigh upwards of seven pounds and is considerably bigger than its relative, the rabbit), the hare is adept at keeping a low profile. It can remain unsuspected in a district for many years, known only to those who are out and about at dawn and dusk, when hares are chiefly active, or who are lucky enough to glimpse one at some other time or find its traces.

This stretch between Flaunden and Chenies remains ideal hare country, with a fair amount of open and semi-permanent pasture, arable land, and a substantial amount of woodland, for the hare is just as much at home under the trees as it is in the open. Formerly there was a small but constant population of hares on the golf-course and in the adjoining Whippendell Wood at Watford, but human disturbance there is now too great and all but a few have gone.

The hare's main requirement, besides a supply of food, is a quiet, safe place where it can lie up during the day. Such a place is called a form and is usually a mere depression in the turf, preferably with overhanging grass stems or other vegetation to keep the hare out of sight. One hare may have many such forms in a small area, and when flushed from one will run to another to hide.

It is usually very difficult to flush a hare from its form, and it will remain there until the last moment, almost until you tread on it. Like most vegetarians of its size, it relies on being overlooked by predators. The eyes are so placed that it sees better to the rear than to the front; the eyes themselves are large and efficient and designed to give early warning of danger. Together with a very acute sense of smell and sensitive hearing which is enhanced by the large and controllable external ears, the eyesight makes it all but impossible to approach a hare undetected. You can be sure that if you can see the hare, the hare has long ago known all about you.

Once it does start running, the hare can cover the ground at up to thirty miles an hour, making short work of rough terrain. For preference it will run uphill, to get the best from those long hind legs. It is an able swimmer and will not hesitate to cross even quite wide rivers.

Unlike the young of the burrow-nesting rabbit, the newborn leverets are fully clothed and can see almost immediately. Two to five in number, the brood is placed in a special form by the mother and left alone while she goes off to feed; she suckles them at night.

Waiting here at the edge of the field, it seems that the hares are not going to reappear today. The bucks are in their forms, and so is the doe. Perhaps she is already pregnant and, as you start for home at last, you wonder whether there will be leverets again this spring in the same place by the edge of the wood, where the grass is sweet and tussocky, under the resinous young branches of the Scots pines. As long as there are, all is not lost for our countryside.

Herons

The telescope is set up on its tripod and turned to medium power. In the clear circle of light there is a grey, fluffy, and rather comical-looking head, poking above the edge of the nest.

A moment later another head rises behind it, another chick: there are three in all, and they have just become aware of the return of one of their parents. Reducing the magnification, we are just in time to include within the circle the adult heron as it arrives, ruffles and then sleeks its plumage. Zoom in again, to maximum power, and we see the adult bird lean over and open its bill.

All three chicks strain upwards to be fed, but only one is selected, either through the discretion of the parent, sharing the food out equally, or because the chosen chick is more pushy than the others and does not scruple to take the food intended for its fellows.

With a gulping motion the parent bird regurgitates the contents of its crop and passes to the chick a semi-digested mash of fish, with a leavening of frogs, perhaps, or a rat or water-vole – delicious for baby herons and, for the moment, the chief interest of their lives. The parent has spent an hour or two collecting it, at any distance up to twelve miles from the colony, but probably no further away than the adjoining lakes and streams.

Only in recent years have herons begun to nest locally again. Several decades ago there was said to be a small heronry at Charlotte's Vale, near Grove Mill at Watford, but otherwise the only nest-site was at Marsworth Reservoir, Tring. Then, in the seventies, herons began to take an interest in Broadwater, a large flooded gravel-pit near Denham.

Before excavation took place, the contractors agreed plans to leave a specified number of islands in the lake. The largest group of these, in the southern end, has now become covered with alders, birches, and willows, and provides a sanctuary for a variety of breeding and roosting birds.

For years the herons were to be seen hanging about the islands during the breeding season. Finally, after a number of false starts, some nests were constructed and the colony began. By now there are twenty or more nests to be seen every spring: bulky platforms of sticks, lined with twigs and other bits of vegetation, sometimes built from scratch, but more often based on the previous year's and enlarged. The female does the building work, while the male provides the materials.

The breeding season begins early, for the heron is a large bird and its young take a long time to grow. The eggs, normally three to five in number, are laid in February or March, and are incubated for about twenty-five days. The young are ready to leave the nest about seven or eight weeks later.

By the end of May or early June, the young herons, wearing the drab grey plumage of the juvenile, have flown the nest. Some remain at Broadwater, loafing about on the islands or shore or perched on the colony trees, but the rest disperse quite widely over the surrounding district.

The colony at Broadwater has proved a great success, and an offshoot has now been established among the wooded islands and gravel strands at Stocker's Lake, a couple of miles to the north.

As a result, the heron, once noteworthy away from its recognized haunts in the Colne Valley, is now becoming a frequent visitor to many sites where previously it was virtually unknown.

While they show no sign of breeding again at Charlotte's Vale, the herons have adopted one particular field there as a daytime roost. Here they wait, digesting their food, until darkness falls and it is safe for them to return to the streams and rivers that, during the hours of daylight, are prone to human disturbance.

The field is broad, sloping, and roughly triangular, bounded on one side by Grove Mill Lane, on another by a narrow strip of woodland beside the River Gade, and on the third by more extensive woods adjoining the golf-course. On a high part of the slope is a single large cedar of Lebanon; the herons either perch on its branches, or on the ground elsewhere in the field – often beside the wire fence parallel with the river. As many as fourteen birds congregate here during the day from September to March, although four or five is a more usual number.

By late January most of the breeding birds have already returned to the Colne Valley to stake their territories among the trees and repair the nests in readiness for another generation of young.

Gravel workings such as these at Broadwater are often criticized for the damage they cause to the environment, and certainly much has been lost here – the botanically rich Harefield Moor has been virtually destroyed. Nonetheless, there are compensations, of which the heronry is one of the most interesting and exciting.

On this cloudy afternoon at the end of March, the colony is in full swing, with as many nests occupied out of sight as are in plain view. The air above the trees is full of parent birds coming and going, and it looks as if a bumper crop of chicks is again to be brought off this year.

Croxley Moor

Some of the best places for the naturalist are those that, on the face of it, seem the least promising or prepossessing.

The Holywell industrial estate, on the borders of Watford and Croxley Green, is an example. Until the recent redevelopment of Dickinson's Mill and the expansion of the rest of the estate, it was always worth a visit, especially in the evenings and at weekends when not too many people were about.

The expanse of mown grass, in season, sometimes produced passage wheatears. The thistles and burdocks attracted many cardueline finches – mainly goldfinches and linnets, but also redpolls. The streams, ditches, and wet thickets provided breeding for blackcaps and sedge warblers, with woodpeckers in the older timber.

A sizable birchwood at the end of Greenhill Crescent – good for fungi in the autumn – has now vanished and its site is buried under factories. The area of woodland and scrub between the Sun Printers and the canal has been razed, destroying a number of notable botanical sites.

Not far from the old Sun Printers clock tower, for instance, among the concrete foundations of a derelict building, was a good variety of grasses, some common and others less so, but all growing untrampled and undisturbed. The surrounding scrub, neglected for years, was, thanks to the buddleias, sallows, and other shrubs that had established themselves there, one of the richest places in the district for butterflies and moths. The waste ground yielded many interesting exotic and alien plants, notably a colony of cypress spurge and, not quite so unusual, but colourful in the late summer, a mass of purple toadflax along the wire fence of the Post Office compound in Ascot Road.

The uses to which man puts the land are often, if not usually, detrimental to other living things. But, immediately his intervention stops, nature begins to take over again. Within a week of its opening in 1973, a new section of the Watford road system had been invaded by several species of weed, growing in cracks between the brand-new concrete blocks.

The new factories, once they have served their purpose, will eventually fall down. Whether it takes fifty years or five hundred, nature will get the land back.

At the edge of the Holywell Estate this process can already be seen in action. The old railway line from Oxhey to Rickmansworth was dismantled in the seventies. No longer sprayed or weeded by the track crews, the shingle bed, running beside Croxley Moor for much of its length, quickly became home to a great variety of beautiful wild flowers. Among these were Pyrenean and long-stalked cranesbills, fumitory, moon-daisy, valerian, and two species of poppy – nothing especially rare, but all plants that are less and less easily found these days.

A little further along, the course of the railway runs between a small marsh on one side and the river moor on the other. Part of the moor has been dug for gravel, leaving a network of flooded pits. The water vegetation has encroached on the embankment and the track itself, and a yard or two from the shingle is a reed-bed with nesting reed warblers. When the air is momentarily quiet, the breeze in the stems generates exactly the same magical rustling that can be heard in the vast, wild marshes of the Danube or the Camargue. If the warblers are singing the illusion is complete.

The track has also been invaded by trees. The young alders and willows form a corridor lined in spring with catkins. Elsewhere there are birch saplings, lots of them, providing shelter for insects and winter food for birds. The birch is a pioneer species, always ready to colonize vacant ground. It is tough, hardy, but short-lived, and provides shelter for more durable trees that come in its wake. Already there are several small oak trees among the birches; if left to themselves they will continue to grow for centuries.

The absence of maintenance has allowed a hawthorn bush to develop into a huge, densely thorned mass, ideal for nesting blackbirds and long-tailed tits.

If you squat on your haunches, or better, kneel down with a lens, there is another, miniature flora to be seen on the thin soil that has already accumulated on the surface of the roadbed. By the end of February the tiny white flowers of whitlow-grass are in bloom, supported on threadlike stems no more than an inch or two high. Later come other dwarf flowers, all adapted to exposed conditions or thin soil. Among these are both our native species of sandwort, with minute flowers that can only be dissected by means of the finest needles.

Where the line used to cross a small stream there is a little bridge in grey engineering brick, which now supports a microscopic flora of its own. Besides the velvety cushions of moss there are grey lichens, strange organisms that share the characteristics of both fungi and algae. And then, yet further along, the mortar of the bridge over the canal is home to a colony of a curious little fern called wall-rue. Swallows nest under the bridge, swooping in and out through the echoing space above the water.

Or at least they used to. There are new earthworks going on now, and lorries rumble back and forth over the bridge. This spring the swallows will probably choose another site. But, so soon as the lorries have gone – next year, the year after, or even the year after that – we can hope and reasonably expect the swallows to come back.

Bumblebees

Spreading along the base of the house wall is a large and old-established clump of _Aubrieta_ , making a mass of small, purplish-lavender flowers. Because the wall is sheltered and faces south, the flowers always come out early and attract any bees that may be in the vicinity.

At lunchtime, when the sun was especially warm, a bumblebee was clambering from flower to flower, taking nectar and pollen. It was a large bee, a queen, with long, silky and luxuriant fur, black except for the buff collar, belt, and tail. Close inspection revealed that the hairy "pollen baskets" on the hind legs were not being filled. Instead she was feeding directly, as if stoking up after a long winter spent underground.

Although a few individuals of some species break their hibernation as early as February if the weather is mild, most emerge in April or early May. Like the smaller honey-bee, the bumblebee is a social insect and nests in colonies. Unlike the honey-bee, though, no worker bumblebees survive the winter. When she emerges in spring, the queen bumblebee must found a new colony from scratch.

Many of the really common species nest underground. Once she has replenished her reserves of fat, the queen searches for a likely site. Often an old mouse- or vole-nest will be taken over, and the bedding left by the previous occupants is rearranged according to her taste, forming a hollow chamber about the size of a fist, lined with the finest of the nest material.

Insects are cold-blooded, but bumblebees are able to generate heat, both by changes in body chemistry and by a muscular movement rather like shivering. During and just after nest-building, the queen becomes "broody" and her body temperature rises. She may sit in the nest chamber for long periods before the eggs are laid, and her body warmth removes any trace of dampness from the bedding.

Once the chamber is ready, she goes out foraging for nectar, which she brings back in her crop. Some of this is smeared on the inside walls of the chamber, helping to consolidate the nest material, and serving also as an emergency supply of food in the event of bad weather.

The eggs of a bumblebee are white and sausage-shaped and about two millimetres long. They develop in eight tubes that arise from the two ovaries, so that, in some species, only eight eggs are laid at a time; others may lay sixteen.

During her foraging the queen also brings back pollen, which she moulds into a lump in the centre of the chamber. The eggs are laid in this pollen, and then covered with the wax that she secretes from glands in her abdomen. The wax canopy extends to the floor of the chamber, helping to hold the egg-clump in place. The queen sits on top of the clump, using her body-heat to brood it.

Wax is also used to make a special pot for holding a reserve of nectar. The pot is usually placed near the entrance, so that the queen, while she is brooding, can extend her tongue to feed. She faces the entrance as she broods so that she can repel intruders – predators, other queens who may want to take over the nest, or queens of the cuckoo-bumblebees that will destroy her own brood and put another in its place.

The eggs hatch after about five days. The grubs feed on the pollen in the clump, which the queen now replenishes with further foraging trips. She must not spend too long away from the nest at this period, or the temperature of the clump will fall and development of the brood may be retarded. If the temperature drops below 10°C they may even die.

The grubs turn into pupae, spinning papery cocoons for themselves. At this stage the queen scrapes most of the wax from the clump and constructs a new layer or row of cells in which the next batch of eggs is laid.

The pupal stage lasts about a fortnight. About five weeks after the first eggs were laid, the first generation of young bees emerges. These then become the first workers, helping with the care of the later broods. The workers are always females, which are produced as a result of sexual reproduction. The males, or drones, are produced from eggs that are not fertilized. They are born towards the end of the life of the colony, and play no part in foraging or nest-maintenance.

At about this time the new generation of queens is also raised. Queens differ from ordinary females only in the care that they receive in their early stage, being supplied with very much more food than a developing worker.

The males leave the nest almost as soon as they are able to fly, and spend an idyllic, if short, existence, lazing about on flowers, needing to feed only themselves, and engaging in elaborate ceremonial flights designed to attract a mate. When the young queens emerge from the nest, they locate the males at visiting-places that are usually marked by scent and may have been used for the purpose by generations of bees. Most females will mate only once, and then, a supply of sperm stored in their bodies, seek out places in which to spend the winter months.

Meanwhile the workers of the old colony gradually die out – foraging is a dangerous business, with many casualties – and, by the onset of autumn, the queen herself, exhausted after all her efforts, is also dead. The first frosts kill off any stragglers, leaving only the young queens to carry on the species.

And now, after a winter spent in suspended animation, they are groggily emerging, like the queen feeding on the _Aubrieta_ by the wall. Soon she will have to find a nest, and then it will begin all over again.

Introduced Trees

In recent years hundreds of thousands of evergreens have been planted by English gardeners, whether for hedging or as specimen conifers. Many of the trees sold here belong to a species called Lawson's Cypress, which has been bred into a bewildering variety of cultivars and crossed with other cypresses to make such hybrid forms as the Leyland Cypress. The Western Red Cedar or Arbor-vitae is another common kind, and there are several others.

Most of these come from the western seaboard of North America. The climate there is mild and equable and ideal for trees: the giant redwood is one of the most famous inhabitants of the forests at California and Oregon.

Our own climate is also oceanic and in certain ways is even better for the growth of trees. What some people might not guess is that the tiny conifer bought today at a garden centre may – unless it is a specially-bred dwarf form – have the potential to grow to a height of a hundred feet or more.

The suitability of Britain for trees is not reflected in the diversity of the native tree flora. Britain was cut off from the rest of Europe at a fairly early time. This, together with the fact that the ice sheet came as far south as the Thames, combined to deprive us of many sorts of plants, including trees, that are common on the Continent, and our native flora only has about thirty-five species of trees.

However, conditions here are just about perfect for the sustained slow growth that makes the finest specimens, and our introduced tree flora is one of the most varied in the world – containing at least 500 species to be found generally, along roadsides, in parks and gardens, and over 1,200 more in special collections. One such arboretum at Westonbirt, in Gloucestershire, has no fewer than 540 different species.

Once started, tree-watching can become a compulsive hobby. All you need is a good book – trees have the great merit of not running or flying away when you get near them, and can always be revisited with a more knowledgeable friend if you are not sure of your identification.

The charm of trees is not easy to convey in words. Their obvious qualities of permanence, grace and silence lend them nobility. Each species has its own particular style, its own solution to the problem of life, that colours everything it does and every particle of its substance.

When you are examining closely, under a lens, a spray of pungent Incense Cedar, or a shoot of Hornbeam or Silver Maple, you enter another realm where normal scale does not apply. Each leaf is perfection, complete in itself. No matter how many times it is replicated, the quality is maintained, the flavour of the tree remains intact. The flavour extends to the shape the tree makes in the landscape, and here again each species is unique. An expert can tell one kind of poplar from another while passing in the train.

For tree-addicts there is no arboretum locally, and excluding Kew and the London parks, the closest collection of any merit is at the Savill Garden, near Windsor. Nonetheless, you do not have to go far to find unusual trees – probably no further than your nearest street-planting or municipal park.

Cassiobury Park, for example, is the next best thing to Watford's own arboretum. Especially in the area near the Shepherd's Road to Stratford Way path, there are many fine specimens of North American oaks – including Red, Pin, and Scarlet Oaks. To the east of this path are specimens of such exotics as Hupeh and Kashmir Rowans, Sweet Gum, Indian Horse Chestnut, and Monterey Pine. Near by, standing with Cedars of Lebanon, is a young Giant Redwood and, by the croquet lawn, a Japanese Red Cedar.

Further down the hill is a Tulip Tree, and near the paddling pool are many Western Balsam Poplars; by the river, next to the children's railway, is a single specimen of the Swamp Cypress, a native of the southern USA. and one of the few trees in the world able to thrive with its roots submerged in water. The black, boggy soil by the Gade is perhaps the best place for it but even so it looks ill at ease, like an animal in a zoo cage, and you come to realize that it really has no business there.

However much fascination exotic trees add to the view, there are not many to compete with our own natives in planting schemes, formal or otherwise. The colours of the beech and oak are in complete harmony with the colours of English skies; and to these trees, and to the kind of forest they make, our native animals and lesser plants are completely adapted.

The exotic trees are comparatively lifeless. Some birds, including the Greenfinch, are slowly learning to exploit the sterile conifer hedges, but compare the number of nests to be found in a hedge of hawthorn or yew. Pressure on land is now so intense that there can no longer be much justification for planting alien species.

And, if you are thinking of buying a conifer this weekend, it might be a good idea to leave enough money in your will for your children to buy climbing irons and a pruning saw!

Tring Reservoirs

The Chinese are credited with inventing (besides gunpowder, spectacles, and the concept of money) the canal lock, enabling boats to travel uphill and down.

It is a clever idea, but has one drawback. Every time the lock gates are opened, tens of thousands of gallons of water must be released downstream. If there is much traffic, a serious water shortage can develop.

The Grand Union Canal, despite making a number of detours to avoid the highest ground, must somehow get past the Chiltern Hills on its way from London to Birmingham. The summit is reached just north of Tring, and there is a series of closely spaced locks in both directions.

To help supply the water for these locks, reservoirs had to be provided, and were dug out by teams of "Navvies" on marshy ground near the village of Marsworth.

Four were built in all. The largest, at 120 acres, is Wilstone Reservoir; the other three, Tringford, Marsworth, and Startopsend Reservoirs, are grouped together a little way to the east and total 90 acres between them. In total they hold a maximum of 460 million gallons; or about 10,000 locks-full.

Thirty years ago the Nature Conservancy leased from the British Waterways Board (then the British Transport Commission) the banks and woodland at the reservoirs, and the area was designated as a National Nature Reserve.

Situated as they are on ancient marshland, the reservoirs have an interesting flora, with such rarities as the orange foxtail grass, round-fruited rush, and mudwort, and some quite scarce insects that are also relics of the former marshland.

But it is for birds, especially water birds, that the reservoirs are best known. It was at Tring that Julian Huxley carried out his pioneering study of the great crested grebe, and ornithological history was made in 1918 when no fewer than three pairs of black-necked grebes bred, the first ever confirmed breeding record in England. History was made again in 1938 when a pair of little ringed plovers brought off three young at Startopsend – the first known breeding in Britain of a species that has now colonized much of the country.

Startopsend is entirely surrounded by embankment, but the others have partly natural shores, with extensive reed-beds at Wilstone and smaller ones at Marsworth. The reeds provide a haven for surface-feeding ducks – mallard, teal, shoveler, and wigeon – and on the open water are diving ducks such as tufted duck and pochard and, during winter and early spring, goldeneye too. Rarer ducks can also be expected at any time, as well as wild swans and geese.

The site of the reservoirs, at a gap in the Chiltern escarpment, makes them ideal for attracting migrants, which tend to get "funnelled" through geological features such as this. The reservoirs are especially attractive to migrating waders, which otherwise might not make a landfall in the county, and it is for unusual waders that Tring is perhaps most visited by bird-watchers.

The spring wader passage is now nearing its height; the autumn passage, which is generally heavier, with a greater variety of species, peaks between late July and September. The water levels fluctuate a good deal, as might be expected, usually being highest in winter and lowest in late summer. The best time to see waders is when the level is somewhere in between, for their feeding areas are found in zones of soft mud and shingle that are covered when the water is too high and tend to dry out if it gets too low.

The early morning after a night of drizzle, with overcast skies and a persistent north-easterly wind, is the perfect time, provided the levels are also right. One such morning in August, after a night of gale force winds, produced common, green, and wood sandpipers, greenshank, ringed plover, snipe, lapwing, and even a red-necked phalarope. On other mornings there were dunlin, redshank, little ringed plover, ruff, little stint, and curlew.

Among the most productive spots are the broad expanses of shingly mud at Tringford, the southern corner of Startopsend and, at Wilstone, both the marshy area at the southern end and the long sweep of the south-eastern shore, which, fringed with reeds and backed by aspen woods, is very lovely.

Indeed, the reservoirs have their attractions for humans as well as birds. Whether visited for bird-watching or simply a stroll, they rarely fail to raise the spirits. Even on sultry afternoons there always seems to be a breeze blowing across the wide water of Wilstone. The air comes through the gap in the hills; distant views of the Wendover Chilterns, stretching right round from the south to the north-east, give a sense of openness and freedom and, from the slight hillside that rises above the aspens, there are extensive views of the vast emptiness of the Aylesbury Plain.

The Grand Union Canal, built between 1793 and 1805, was one of the biggest engineering projects of the age, comparable with the construction of the M25. Doubtless little thought then, as now, was given to the effect it was having on the countryside; but with the canal system, where transport is conducted on a gentler scale, we have been lucky, and, for Tring Reservoirs, must not forget in our gratitude to acknowledge those wily Chinese.

Hydra

It is an hour after tea and from the row of deckchairs comes an occasional ripple of light applause. The home team is all out for a respectable score, and the visitors have just gone in to bat.

What could be more innocent and peacefully English than a village common? But behind the cricket pavilion is a small pond bordered with rushes, where not all is what it seems.

Earlier today, using our trusty grapnel, we took a few strands of weed from the middle of the pond and placed them in a large jar of water. By lunchtime a good many of the small creatures in the weed had made themselves evident.

The animal we were seeking was among them. Clinging to the glass were several threadlike specimens, two or three brown, but mostly green, of one of the strangest and most treacherous denizens of the underwater world, a tentacled relative of the Portuguese Man-o'-War, of the sea anemone and the coral, with a name from Greek mythology and a ferocious armoury of poison darts with which it spears its hapless prey.

Luckily for those who like to walk the common in safety, all this goes on in miniature. Not counting the tentacles, the biggest specimens are not much more than half an inch long.

_Hydra_ – for that is the creature's name – consists, besides its half-dozen or so tentacles, of a tube-like body and little else. The base of the tube is formed into a disc-shaped foot, with which it anchors itself to a stone or frond of weed. If all is well, the tentacles are extended and gently waved, and _Hydra_ waits for chance or the current to bring it what they may.

In common with most of the coelenterates (the group of "hollow-bodied" animals to which it belongs) _Hydra_ is equipped with stinging cells called nematocysts. In its most highly developed form a nematocyst consists of a capsule filled with poison and containing a long, hollow filament, at the end of which is a more or less elaborate arrangement of barbs.

Projecting from the mouth of the capsule is a short trigger that, when activated by a passing prey-animal – often a water-flea – sets off the release mechanism. The capsule violently contracts and the barbed head of the filament is shot out like a harpoon, puncturing the body-wall of the prey and releasing the poison inside.

Besides these so-called "penetrant" nematocysts, _Hydra_ 's tentacles have "volvent" nematocysts also. Volvents are likewise used in feeding. Once the prey has been stunned or killed by the penetrants, the volvents are discharged. They have no harpoon or poison, but their filaments are designed to coil round bristles and other projections on the prey. Muscle cells in the tentacles then contract and the prey is brought inexorably to the mouth, which is no more than a hole at the apex of the body, in the middle of the ring of tentacles.

Digestion is a pretty straightforward business for _Hydra_. The cells lining the body cavity secrete enzymes which help to break down the food, and mechanical action (which occurs whenever _Hydra_ moves about) does the rest. Nutrients are absorbed and dispersed either by simple diffusion or by cells that migrate about inside the animal, taking the food where it is needed. Unwanted material is egested through the mouth.

Nor is _Hydra_ 's sex-life much more complicated. Usually it does not bother at all, and merely grows buds that, enlarging, eventually drop off and become a new individual. This enviably simple process is only suitable as long as the water remains warm, for _Hydra_ cannot survive the winter in adult form.

In autumn, then, certain cells develop in the body wall that become testes. Lower down on the body an ovary also develops, but not at the same time, so that self-fertilization is rare. The covering on the testes finally ruptures, releasing sperms into the water that seek out a ripe egg. The resulting zygote develops into a cyst that sinks to the bottom of the pond and lies dormant till spring, when it soon hatches and grows into an adult _Hydra_.

The mythical _Hydra_ had frightening powers of regeneration, growing two heads for every one that was cut off; and our local _Hydra_ is not far behind. It can replace a mutilated, or even a completely amputated, tentacle. Even if the body is cut up into tiny pieces, each one will develop into a new individual.

This is made possible by a layer of "interstitial" cells, each of which is a basic and undifferentiated cell, waiting to turn into whatever is needed. The interstitial cells are the reservoir from which the nematocysts are replaced, and from them the sexual organs develop too; it is likely that a new _Hydra_ could grow from a single interstitial cell.

The green _Hydra_ gets its colour from the presence in its body wall of _Chlorella_ , a single-celled plant that is a degenerate relative of the free-swimming algae present in almost any bit of stagnant water. _Chlorella_ and _Hydra_ exist in partnership: the plant absorbs carbon dioxide and minerals from the animal and gives back oxygen and excess sugars.

Having studied our specimens long enough, it is time to put them back. The cricket is still in progress; by now a number of those in the deckchairs seem to have fallen asleep. It would be a shame if their dreams were ever inhabited by monsters as fearful as those that, as we empty the jar into the pond, are now returning to their own murky world.

Bluebells

Among the many sights and sounds to be treasured from this evening's walk through the woods and fields is one that never fails to come each spring, yet never fails to surprise.

Each day now the twilight lasts longer and longer, and once the sun had set the thrushes continued singing almost until darkness. A cuckoo was calling very late, and after nine o'clock I passed through the northern end of Harrock's Wood, where, under the hazels, a seemingly solid yet insubstantial mass of bluebells stretched into the wood for as far as the eye could see, the colour deepening and becoming more mysterious with the dusk.

For those plants that grow in the woodland understorey, the single most important factor is the amount of light available, and most of them, the bluebell included, must get their flowering finished before the full canopy of leaves is out.

In the first half of May the leaves of the dominant woodland trees begin to emerge from the bud-cases in which they have passed the winter. At first the leaves are pale-green, soft, and almost translucent, but they quickly harden as the chloroplasts – the chlorophyll-containing bodies – are brought into use, and within a week or two the tree is a fully functional factory, running on sunlight and producing sugars and oxygen.

The bluebell is tolerant of shade, but does not need it and grows well in full light. The reason it is primarily a woodland flower probably has something to do with the greater humidity to be found inside a wood: bluebells have exacting requirements for moisture, and the soil must be neither too damp nor too dry. They also like ground, such as that in a wood, that remains undisturbed for many years, and the best displays are always found in old-established woodland.

With its blade-shaped leaves and long hollow stalk or scape, the bluebell is a typical member of the lily family – which also contains such oddities as the asparagus, tulip, onion, and garlic. The flowers are bluish-violet because that colour appears most prominent to the ultraviolet-sensitive eyes of the insects that pollinate them, and are carried, up to sixteen at a time, in gracefully drooping, one-sided racemes. The anthers are creamy white, unlike the blue anthers of the garden or Spanish bluebell, _Endymion hispanicus_.

The wild bluebell is rather puzzlingly called _Endymion non-scriptus_ , or "not written-on". Gerard, the herbalist, in 1597 described the "Blew English Hare-bels, or English Jacint", jacint being another spelling of "hyacinth". Among the ancients, jacint or jacinth was a rare gem of blue colour, probably sapphire. Then, recounted by the poet Ovid, there is the legend of Hyacinthus, a youth "beloved of Apollo", as the phrase discreetly puts it. Hyacinthus was accidentally killed by Apollo (another version blames Zephyrus, the West-wind), and on the spot where he died a flower sprang up – the lily or hyacinth. On the petals Apollo inscribed the letters _AIAI_ (the Greek word for "alas!"), which can indeed be seen on certain sorts of lily to this day.

The early herbalists tried to describe everything in terms of classical learning. The bluebell was plainly a hyacinth of some sort, and was originally placed in the genus _Hyacinthus_ , but the word AIAI was not to be found on its petals – hence it was _non-scriptus_.

William Turner, in the third part of his _Herbal_ , published in 1568, recommends the bluebell as a remedy against spider-bite, an idea pinched from the Greek writer Dioscorides, who was anyway describing another sort of hyacinth. Turner also says that the boys in his district "scrape the roote of the herbe and glew theyr arrowes and bokes wyth that slyme that they scrape of", and indeed the slimy sap of the bluebell can be boiled down to make a strong and practical glue.

This sap covers the fingers of those who indulge in the mindless and illegal habit of bluebell-picking. The peculiar noise and feel of the stems when they are broken has given rise to one of the bluebell's most vivid vernacular names, "snapgrass". The Victorian poet Gerard Manley Hopkins writes in his journal: "The stalks rub and click ... making a brittle rub and jostle like the noise of a hurdle strained by leaning against", which is as apt a way to put it as can be imagined.

He also describes the bluebells making "falls of sky-colour"; bluebells are seen at their best where they grow in sheets and clumps and spread a broad carpet of blue. As soon as they are picked, within minutes, they begin to droop, and in a vase or jamjar at home they look completely miserable and out-of-place. It is much better to leave them for others to admire.

If the truth be told, picking the flowers does less harm than treading on the leaves, which are fleshy and easily damaged. The bluebell spends the dark summer under the trees in renewing the food reserves held in its bulb, and if the leaves are squashed the whole plant will become sickly or die.

Private, relatively untrodden woodland, like Harrock's Wood, is the place to see bluebells in the mass; but even in overused woods, litter-strewn hedgerows and spindly copses, bluebells in healthy groups are still a frequent sight. Perhaps they are more resilient than they look.

Swallows

"One swallow does not make a summer", but tens of thousands do, and now that they are here in force we can safely say that summer, in its broadest sense, has arrived at last.

The swallow is not the first of its family to appear: the sand martin is usually the earliest. The swallow itself is next, and then the house martin. Finally, on or about 23 April, comes the swift – which is of course not a member of the swallow family at all.

The four birds each catch their insect food in flight, and although superficially similar, are not difficult to tell apart. The swift is wholly dark except for a pale patch on the chin, and has very long, scimitar-like wings and a short tail only moderately forked. The three hirundines also have forked tails, but their wings are shorter, and they are all white or whitish below. The sand martin has earth-brown upper-parts, the house martin and swallow dark blue, but the house martin has a distinctive white rump by which it can be told even at a great distance.

It would be hard to think of a more pleasing or attractive bird than the swallow, or of one that adds more charm to the countryside. Its generally low, graceful flight is marvellously smooth and controlled, swooping over a cornfield, endlessly quartering the broad expanses of pasture where sheep or cattle are grazing, by whim turning to left or right when coming to an obstacle, or, inches from the turf, skimming among the boles of standing trees.

The swallow is such an exact and delicate artist of flight that it drinks on the wing, dipping its lower mandible into the surface film of the river to scoop up a little water. When it wishes to bathe, it descends an inch further, douses itself, and then rises to complete its toilet in the air. It rarely settles on the ground, except to collect particles of gravel for its gizzard or materials for its nest, and almost all of its food – mainly gnats, flies, and small beetles – is taken on the wing.

The elegance of the swallow's flight is matched by the beauty and rightness of its plumage. The dark blue upper parts have a metallic sheen, varying almost to dark green depending on the angle of the light. In the adult male especially, the outer tail feathers are attenuated into streamers that can be fully two inches longer than the next feathers in. The tail feathers are not blue, but a deep bottle-green, marked on their inner webs with spots of white. Below, the swallow is buff on belly and underwings, with a metallic blue band across the chest and, setting off all the rest of the colours, a dark chestnut throat and face.

The female is normally rather whiter below, with shorter streamers. She and her mate always return, if possible, to the same nest-site year after year. The favourite place is a ledge or rafter in a barn or outhouse, although at one time the deep recesses of large, old-fashioned chimneys were much used.

Before the widespread construction of buildings, the swallow must have been quite a rare bird in England, for its presumed natural nesting sites – caves and sheltered hollows in rock-faces – are few and far between. Since the time of the Romans, it has become completely adapted to using human "caves" for its nests, and is now one of the few species, like the house sparrow, which is more at home with man than in the wilderness.

The nest itself is made of mud, collected from puddles and riverbanks and reinforced with shreds of grass. It is in the shape of half a saucer, and is lined with the softest bents and feathers (the latter often collected in flight).

The eggs, normally 4-6, are white, blotched and speckled with russet and grey, and are incubated mainly or completely by the female. They take a fortnight or so to hatch. Both parents feed the young, which must be a daunting task, bearing in mind the slightness of each catch. This could be one of the reasons why the young take a comparatively long time – about three weeks – to leave the nest. As soon as they can fly and feed themselves, the parents begin another brood, and there may even be a third.

So strong is the urge to depart in the autumn that when, because of bad weather or through some other delay, this third brood is late in the year, the nestlings may be abandoned and left to starve.

For the early naturalists the swallow was the summer visitor that most exercised their curiosity. In one camp were those who believed, as the Greeks had done, that swallows and martins spent the winter either in the mud at the bottom of ponds, or in hibernation in a hollow tree-trunk or cave; in the other were those who believed in migration.

The advent of modern travel and bird-marking with leg rings settled the matter, and now we know that the swallows that nest here winter as far south as the Cape.

There they remain until late February or March, when, covering a hundred miles or more each day, they begin to make their way northwards. Once over England, the swallow migration progresses in a broad front, with a tendency to follow river-valleys where these run in the right direction.

And finally, within a few days on either side of 6 April, the swallows again return and bring their delightful presence to make us yet another summer.

Plant Odours

The accurate identification of wild plants is not always easy, and the botanist must use all his faculties in trying to track down a name for his specimen. One of the most useful yet unreliable senses is that of smell: unreliable because no two people ever seem to react in quite the same way to the same odour. To quote Linnaeus, the founding father of modern systematic botany: "... a scent which is disgusting to a boy is most pleasing to a hysterical woman. A countryman entering a drug-store turns faint with the scent of the perfumes, but recovers when a heap of cow-dung is presented to his nostrils ..."

Besides which, smells usually defy description. The human sense of smell is not very acute, and our language simply has insufficient words for the job.

One of the strangest and most characteristic odours in the plant world is generated by the foliage of the hound's-tongue, which smells of mice. For me this invariably generates memories of the north Norfolk dunes where I found my first specimens: a commingling of marram, hot sun, and the resinous drift of the air through Corsican pines. Any description that I attempted of the smell of hound's-tongue would be coloured by this, and meaningless to anyone else.

Nonetheless, a plant-smell, once learned, can be a powerful aid to the memory, even if this knowledge must remain a personal thing and incapable of being accurately transmitted to others.

Animals have no such problems. They have no urge to classify or analyse, and smell is simply one part of the whole that makes up their existence. In some groups smell is just as, if not more, important than vision or hearing, and this is true of many insects, for whom, in the main, plants produce their rich and bewildering variety of scents.

The chemistry of plant odours is immensely complicated. The scent is produced by the oxidation, on exposure to air, of essential oils. The oils are stored in special glands, whether in the flowers or elsewhere in the plant. Glands may also be found in the outer skin of stems and leaves, or the oils may be stored in capsules deeper in the tissues, so that the scent is only released when the plant is crushed.

In flowers, these glands are on the upper surface of the petals, or on the sepals or bracts if these replace the petals. The oils are produced continuously; in the final stage of manufacture, the fluid is left as a mixture of oil and sugar, and it is not until this mixture starts to ferment that the scent is released.

The fragrance given off by a broad bank of wild thyme or a hawthorn hedge in bloom will carry a long way, in insect terms. One function of plant odours is undoubtedly to attract pollinating insects: the brighter and showier the flower, the less likely it is to have a strong perfume. Certain moths and butterflies secrete scents similar to those produced by plants, and in many cases these insects will only visit the flowers that smell like themselves.

On the whole, though, scent is thought to be relatively unimportant in bringing pollinating insects from a distance. It is much more important at close range. In experiments with porcelain flower-models, insects approached in the ordinary way, but would not enter until the models had been brushed with scent from a real flower. So it would seem that the scent modifies the behaviour of the insect in some manner, encouraging it to go through those actions that lead to pollination.

Another function of plant odours is to serve notice on a would-be browser that the plant is distasteful or poisonous. The chemicals adopted here are often trimethylamine and propylamine, which are present in the early stages of putrefaction, or indol and its related compounds, which likewise have a horrible smell. When the depredations of leaf-cutting insects and their larvae are taken into account, this must be vital to survival.

Protection from attack by fungi and bacteria is equally important: it has been estimated that the essential oil of thyme is twelve times more antiseptic than carbolic acid. The oils of lavender and rosemary are just as strong.

Thyme, lavender and rosemary are all members of the _Labiatae_ , the family of plants that includes many of our best-known herbs, such as basil, mint, and marjoram. Labiates tend to be plants of dry, open ground and sunny places, and as such need some protection against excessive water-loss. As part of their armoury they are usually thickly coated in fine hairs, which help to reduce evaporation from the open pores or stomata on the leaves.

The aromatic oils produced by these plants also help to reduce evaporation. The oils are not soluble in water and create a haze round the plant, reducing water-loss but still allowing the exchange of oxygen and carbon dioxide to continue in the leaves. Labiates often grow clustered in dense patches, and it is intriguing to think that they create their own protective shell using nothing more substantial than odour.

But how to explain the smell of hound's-tongue? To know that it is caused by esters of certain fatty acids does not get us very far. Nor does it help much to know that the same odour occurs in the entirely unrelated lizard orchid, although both plants are pollinated by bees.

Unless plant-nibbling insects are put off by the smell of mice (or goats, as some people describe it), we are left with as curious a puzzle as could be hoped for. Such are the pleasures of botany.

Weasels

It has been noticeable in the past ten or fifteen years that the rabbit population is recovering after myxomatosis, and numbers must now be approaching something like their pre-1953 level. The new breed of rabbit seems not only more resistant to the myxoma virus, but also more enterprising in choosing a site for a warren.

Along part of Under the Heavens Lane, a deep and narrow thoroughfare running the length of a dry glacial valley, the northern hedgebank is riddled with rabbit holes. The rabbits themselves are multiplying as only rabbits do, and may often be seen sitting by their burrows basking in the sun, or making excursions into the adjoining field for titbits of salad.

The lane is fairly quiet, and the warren, now that farmers have more profitable things to do than set snares, is reasonably safe from disturbance.

Recently, though, this paradise was violated by what must seem to a rabbit like the Angel of Death. From my bicycle this morning I glimpsed a lithe, upright form seated arrogantly on the sawn surface of an old fence post. Its fur, as soft and luxuriant-looking as anything at Harrods, was marked with a pattern of umber and champagne, and made a bandit's mask round the eyes, which had the fierce, mad gleam of the professional murderer.

In the first instant the word "polecat" flashed into my mind; but this animal was too pale to be that, and besides, there are no longer any polecats in this tame, thoroughly domesticated region of the Home Counties. No: it was an escaped ferret, and it had taken up residence in the rabbit warren, to the terror and consternation of all those within.

Now the ferret was living the polecat's life, a far cry from guest appearances at the village pub or spending the evening in someone's trousers. On taking its freedom, it had immediately gone native, true to its nature and ancestry, for the ferret and the polecat are members of one of the most bloodthirsty groups of carnivores there is – the genus _Mustela_.

We have two more members of this genus living hereabouts, the weasel and the stoat. The landscape may be ordered and manicured now, and entirely dominated by man, but their independence remains intact. They are both killers, at or near the top of the food chain, and their style is unmistakably that of the assassin.

The weasel is about seven inches long, three-quarters the size of the stoat. In general pattern they are both, like the ferret, short-legged and long-bodied, built for pursuing their prey through tunnels and burrows. Both have brown upperparts and white underparts, and small, rounded ears that are usually held at an upright and inquisitive angle.

The stoat can always be told by its longer tail, tipped with black. In winter the stoat usually turns white, and then its fur is called ermine, but the black tail-tip remains. In more northerly climes than Britain the weasel turns white in winter too.

Despite rigorous persecution, they both manage to survive in fair numbers, and the weasel may even be said to be common. The most that is usually seen of a weasel is a rapid, low blur as it streaks across the road from one hedge to another. But if you have the time and patience, it is not a difficult animal to observe.

Occasionally you will disturb one in the act and it will drop the mouse or vole it has just killed and flee. Keep absolutely still, wait, and the weasel may very well return, giving you the privilege of perhaps half a minute's clear view.

The best place for observation, though, is at the nest, if you can manage to find one. Weasels breed twice a year, giving birth in April-May and again in July-August to a litter of about half a dozen young. The nest is placed in a hollow tree-trunk or a burrow speedily vacated by a family of rats. Now, at the end of May, the first litters are beginning to be weaned.

The female alone usually rears the young, and she decides when it is right for her brood to leave the nest and take their first lessons in hunting. She will show them what is edible and what is not, and how to deliver the coup de grâce with a quick, savage bite through the back of the neck.

The main prey of weasels consists of small mammals, especially mice and voles. After man, the weasel is the worst enemy of the mole, as is shown by the number of weasels caught in mole-traps. Shrews, though, seem hardly to be taken.

The appetite of a hunting weasel is prodigious. As it is so small, the animal's surface area is large compared with its volume, and it will eat anything up to a third of its own body-weight a day. In practical terms, that means a family of weasels can put paid to two thousand mice and voles a year.

Besides small mammals, weasels are not averse to the odd bit of carrion, to birds' eggs, and to the birds themselves – having been known to attempt one the size of a lapwing. They are fearless, invested with the same instinct as the tiger or puma. In the weasel, and the stoat, there is another element of ferocity too, bordering on the insane.

The cause might be traced to a nematode, a parasitic worm with the unpronounceable name _Skrjabingylus nasicola_ , which is present in 10% of young and 70% of adult weasels. The worm progressively attacks the bones of the skull. It may be that stoats and weasels are driven by their own private demons.

I don't know whether ferrets, gone wild, suffer the same fate. If so it would account for that mad gleam in the eyes; and if so, it does not augur too well for the rabbits of Under the Heavens Lane.

Glaciers

At school we were shown how to make a model of the landscape. Using cardboard and papier mâché, and taking our measurements from the contour lines of the Ordnance Survey map, we gradually built up a rather clumsy version of the local hills and valleys.

Even coated with paint (green for the fields and woods, grey for the built-up areas, and an improbable ultramarine for the rivers, canal, and gravel pits) it was a sorry-looking object, and was quickly put out of sight by the geography teacher. I believe he may have hidden it behind the scout hut. In any case it was not in evidence when Open Day came round.

The forces that moulded – and are still moulding – the real landscape make a much more convincing job of it. They are incomprehensibly vast and slow-moving, like the glaciers that were responsible for carving out the valleys of the Gade, the Chess, the Ver, and the Colne.

The last Ice Age ended here about 12,000 years ago. We are presently in a mild interglacial period: another Ice Age is probably on its way.

The origins of this cyclic advance and retreat of the ice are thought to lie in the behaviour of the southern ice cap. The core of the Earth is still molten, and the heat must escape continuously from the planet surface. There reaches a point when the accumulation of ice in Antarctica is so great, the thickness of the ice-sheet so tremendous, that this geothermal heat is trapped. The base of the ice-sheet melts, is freed from the friction of the underlying rock, and begins to spread over the ocean as a floating mass.

What happens next affects us in the north. When the Antarctic ice reaches an area of about 10 million square miles, its white surface reflects back so much sunlight that the net input of solar heat is reduced by the critical figure of 4%. The planet cools, the northern ice cap enlarges (aggravating the reflection loss), and the glaciers start to advance.

The process goes into reverse when the icecaps reach the warmer oceans nearer the equator. Then the ice shelf is weakened by warmth and physically eaten away by the erosion of the waves. The area of white begins to contract, and the input of solar heat increases.

Here in south-west Hertfordshire (not that such names mean much to a glacier), the vegetation at one time was that of a tropical forest. The valley of the Thames was a steaming swamp very much like something to be found today in, for example, Malaysia. This was about 63 million years ago: over the next 61 million years the climate cooled and our flora became more typical of the temperate zone.

The first major glaciation came somewhere between 800,000 and 590,000 BP. Since then there have been half a dozen more: the third from last, the so-called Lowestoftian glaciation, was the most extreme of all and reached as far south as the Thames basin.

The ice of the Lowestoftian advanced across England in a generally south-easterly direction, flowing and rolling like a slow-motion tidal wave. With it the glacier carried a vast amount of debris, billions upon billions of tons of fragmented rock torn up in its path. Where it met resistance it altered course to some extent through the softer rocks.

In the general trend of our local valleys – from north-west to south-east – we see evidence of the glacier's passage. Nowhere is this more obvious than at the junction of the Rivers Gade and Chess. Both valleys are quite deep, separated, near the junction, by a wedge-shaped nose of land that we call Croxley Green. The Green itself is at the summit of this particular ridge, but even on the Green the land is beginning to slope downwards. The slope accelerates at Scots Hill, and the two valleys converge just north and east of Rickmansworth.

This was the site of a contest between three giants – the iceflows from the Chess and Gade, and the larger flow making its way south along the modern course of the Colne. The battlefield was the wide expanse of Croxley Moor.

The opposing forces then united and continued south, along the present Colne Valley. The glacier got another twenty miles, as far as the Thames, before the climate began warming up again.

In its retreat, the glacier abandoned the rock debris it had brought. This, washed and pounded further by the torrents of meltwater, was left behind as the gravel that has since been excavated in such quantity along the valley of the Colne.

The ice destroyed almost all living matter in its path, and the British flora is the poorer because of it. The landscape after its retreat must have been utterly desolate, and silent but for the sounds of wind, rain, and flowing water.

Since then the harsh contours have been softened by the gentler forces of the weather; the land has been recolonized by plants and animals (including ourselves) from the south. The effect that man himself has had on the landscape, profound as it is, is nothing compared with the work of the glacier. Its scale makes all human efforts seem puny, and puts into perspective our present worries about politics or the price of bread.

However, there is talk of averting the next Ice Age before it even starts. Technically it would be possible, using nuclear explosives, to break up the ice in Antarctica as it formed, and so change the course of geological history.

Comforting as it may be to know that the next glaciation might be stopped, it would be a pity to feel that we had gained control of such a monster as this. Some things should remain sacrosanct.

Perhaps we ought to put this scheme behind the scout hut, where it belongs.

Badgers

Unless you are observant and spend plenty of time out and about in the woods and fields, it is unlikely that you will ever suspect the presence of one of the most charming and yet most ancient of Britons – the badger. For, despite a disturbing increase in the depraved and sadistic practice of badger-baiting, the badger is by no means rare in many parts of England, including our own.

Because of this persecution, it would be irresponsible to name the places where badgers may be found. What safely can be said is that the badgers now have, in the shape of the Hertfordshire and Middlesex Badger Group, a body of dedicated and knowledgeable champions. One of the aims of the Group is to survey the badger population of the two counties, and I was fortunate indeed to be invited by one of the members to accompany her on a badger-watching expedition.

Badgers are sociable and gregarious and live together in a burrow, or set, often excavated on sloping ground. They are industrious workers and can shift surprising quantities of earth. If a set has been established a long time it may become quite a feat of engineering – one in the West Country had 12 entrances and 94 tunnels with a total length of 310 metres, and it was estimated that 25 tonnes of soil had been moved in the process.

The set we were to visit is also well established; according to one nearby resident, it has been in continuous occupation for at least 60 years. The situation of the set is pretty well ideal, in a quiet, little-frequented wood not far from fields that provide a further source of food.

Radiating from the tunnel mouths is a system of narrow, well-defined trackways leading to favourite feeding areas and drinking places, or to other sets in the vicinity, for badgers are fond of visiting their neighbours. Where much used, these trackways become so well worn that they look like human paths, and in fact many of our paths through the woods probably originated as badger-trails.

To a badger, the trails are an informative amalgam of scents: each animal has its own distinctive musk, secreted from glands beneath the tail. Furthermore, badgers of the same social group will put their scent on each other, so that the whole group acquires a unique and corporate musk, quite different from that of its neighbours.

Territories are marked with scent, and with dung, which is often placed in shallow, specially dug pits placed at strategic points on the boundary or beside main trackways. Badgers are fastidiously clean animals, spending much time grooming and scratching, and have in addition special latrines well away from the set.

They also regularly change their bedding, which consists of dry leaves, bracken, and so on. In winter, when fresh bedding is hard to come by, the badgers will wait for a sunny day and leave bedding outside the set for a few hours to air.

The badger is mainly nocturnal, emerging at dusk or shortly beforehand, spending the night feeding or playing, and returning in the morning to sleep. Where undisturbed, as here, the badgers tend to come out earlier, and to be on the safe side we arrived at the wood about an hour before sundown.

Heavy rain had fallen during the day, and the air under the trees was warm, humid, and heavy with the odour of fresh earth and bluebells. The sky had cleared, and there was hardly any wind – a good omen, for even the slightest breeze can carry a trace of human scent to the set. Selecting a place to sit, 25 yards or so from the main tunnel, and with our silhouettes disguised by the background of vegetation, we settled down to wait.

Successful badger-watching demands two things – fortitude and patience. The watcher must keep quiet and still. In winter he or she must endure the cold, in summer the attentions of midges. Then the time of emergence can vary a great deal; the badgers may not even come out at all.

As a newcomer to this activity, I was keeping my fingers crossed and anxiously watched the mouths of the tunnels for movement. None came.

Time passed. The light began to go, and still there was no sign of the badgers. My companion whispered her misgivings. With badgers, as with all wild life, nothing can ever be predicted.

By now we had been quiet for so long that our ears were keenly attuned to the slightest sound. From the dense undergrowth between us and the set came the high-pitched squeaking of a shrew; as the air cooled, condensation dripped from the canopy of trees. Still no badgers. It was beginning to look as if we had drawn a blank.

Then, from the field edge thirty yards away, came a faint rustling, followed by silence. A minute or two later came another rustling, further to the right, and another. There was definitely something moving about. Presently we heard a brief, whickering cry. One of the two cubs – there are two in this particular family, both well grown – was calling. This was followed by a sort of quick bark, made by one of the adults.

The light was now so bad that it was impossible to discern detail with the naked eye. With binoculars, though, a little could still be seen.

Suddenly, there were the badgers, on the bare, worn soil near the main entrance to the set. There were at least four, probably the two cubs and their parents. Obviously, contrary to all expectations, they had emerged even before our arrival. They must have been in the fields all evening, perhaps feeding on earthworms, one of the staples of their diet.

In the gloom, the black and white facial markings stood out plainly. Moving about, attentive to one another, the badgers appeared a ghostly silver. To be seeing such genuinely wild creatures was a privilege; it gave meaning to that overworked word, "thrill".

Unhurriedly, at their ease, the badgers vanished into their labyrinth.

The light had now gone altogether. There could be nothing more for us to see. The badgers had been in view for only a few minutes, but the long wait had been well worth it. Standing up, aware at last of our aching limbs, we reluctantly started for the path.

Snails

The author of a fanciful but intriguing study of ancient man has analysed the rock-carvings at a Stone Age temple in Ireland, and deduces that the priests or shamans who built it had discovered one of the secrets of the cosmos, the underlying plan on which all growth and development are based.

The calculations are beyond me, but the idea is that all development can be reduced mathematically to a single pattern: the spiral, or helix. The spiral is seen in the shape of galaxies, in the flow of water, in the growth of plants following the sun, in the structure of DNA (the basic substance of genes) and, more abstrusely, in a thousand other aspects of the natural world.

Nowhere is this pattern more perfectly expressed than in the shell of the humble snail, such as the one I found this morning on the garden path. Certain species have a shell so regular, so much in accordance with the mathematical theory, that it could have been constructed for the sole purpose of giving it tangible form. But then everything in nature conforms to the rigorous laws of survival, and simplicity and beauty are mere by-products of this strict adherence to function.

The helical shell is a brilliant piece of design. Because of its shape, it can be continuously enlarged without the need for moulting. Insects must cast off their hard outer skeletons at regular intervals during growth, but the molluscs (the group of animals that includes the limpet, periwinkle, and snail), by inventing the shell, have secured permanent protection for themselves.

Originally all molluscs lived in water, and the majority of them are still to be found there, whether in the sea or in fresh water. In making the transition, those sorts that colonized the land met with a new set of problems.

The shell was the main asset that allowed them to make the change, protecting the animal from water loss. The shell is laid down in two layers. The inner one is made mostly of calcium carbonate, but the outer is hard, virtually impermeable, and horny. In unfavourable conditions, a snail can seal the mouth of its shell, either with a horny plate or with a temporary shield of dried mucus, and survive until conditions are more to its liking.

Every advantage, though, has its disadvantage, and the disadvantage for the snail is the weight of its portable home. While saving the animal from extremes of dryness and heat and from smaller predators, the shell slows it down and makes it easy prey for larger ones. A revolting and unmistakable sound made by badgers is heard when crunching snails; and of course song thrushes are well known for their habit of making an anvil – a favourite stone on which snails are bashed to bits. One such anvil I found recently was surrounded by the debris of a least a dozen shells.

Snails do not have a very appealing image, and still less do their relatives, the slugs (which, wisely or not, have dispensed partly or wholly with that cumbersome shell), but they are fascinating and admirable creatures for all that, and deserve a better response than the customary "uurgh" when found lurking behind a leaf or under a stone.

The colours of living snails are very subtle and beautiful and, looked at dispassionately, so are those of slugs. But it is for their biology and behaviour that these animals are most worthy of study.

Both slugs and snails are most active by night, hiding out during the day in some damp place. With a few exceptions, they are vegetarians, eating especially plant material that has begun to decay. That is the reason they can be a pest in the garden: cultivated plants are often much softer and flabbier than their wild counterparts. The food is rasped to pieces between the upper jaw and rows of horny teeth on the tongue; these teeth grow continuously from behind. Snails restrict their wanderings to the surface of the soil or above, but slugs can dig into the ground as far as a metre, and are often the culprits when root vegetables are attacked.

As a student I once had to dissect a snail, which is an experience I wouldn't wish on my worst enemy; and we will not dwell here longer than absolutely necessary. Nonetheless the internal organs, if you can sort them out, comprehensively fulfil all the functions that a snail could wish for.

Most complicated, perhaps, are the organs of reproduction. Snails are hermaphrodite, with a single gonad, which produces eggs for a short period each year and sperms for the rest of the time. As in most hermaphroditic animals, self-fertilization is rare, and the courtship of the snail is not without its own bizarre charm.

The eyes are tiny, usually on the tips of one of the two pairs of tentacles, and the vision is poor, so it is unlikely that the lovers' eyes meet across a crowded shrubbery. Neither could they rush together to consummate the embrace; by the time they made contact they would both have forgotten what they were doing.

No: contact is probably made by smell, for the tentacles are equipped with sensitive olfactory cells. The two snails circle each other, frequently touching, and form in the process a platform of accumulated slime. Finally, the partners discharge at each other what are known as "love darts" – sharp spicules of calcium carbonate, variously shaped, but often winged in cross-section like the feathers of an arrow. The dart lodges in the tissues, where eventually it is absorbed.

It serves as a stimulus for completion of the act. The snails align their reproductive openings, and coupling begins. Sperms are exchanged in the form of packets; fertilization may not take place for up to a year after mating, but egg-laying usually follows fertilization within about a fortnight.

The eggs are laid in the soil. The baby snails resemble the adults in most respects but size and, if they survive, can expect to reach maturity in about a year. The shell is incremented in stages, with material added to the leading edge, so that "growth rings" can be seen on a shell, rather as on a tree stump. When adulthood is attained, the shell usually stops growing and a thickened lip is formed at the mouth.

So ends the mathematical growth of the helix. I wonder if the brown and cream-banded snail I found on the garden path knows or cares much about the underlying forces of the cosmos.

Somehow, I doubt it.

Lapwings

This is shirt-sleeve weather, a day to increase still more the contrast between your forearms and the band of pale skin under the watch-strap, the sort of day when the lubricant loosens in the focusing barrel of your binoculars. The blueness of the sky has been taken up by the air itself. Each detail of the scene appears almost supernaturally clear and sharply defined, given somehow an even greater clarity by the fresh breeze hissing in the leaves of the lakeside alders.

Summer is officially less than a week old, but for some among us autumn is already here. The return migration of the lapwings is nearing its height. During the next two or three months many thousands will pass through the district, slowly making for their winter quarters in the south and west.

Lapwings are birds of the plover family, quite large, seeming black and white at a distance, with wispy crests and characteristically rounded wingtips. They breed in open places, especially on farmland, and can be seen in spring performing spectacular aerobatic display-flights, twisting and tumbling, keeping up a barrage of wheezing cries: frenzied variations on the ordinary note of _pee-wit_ from which the lapwing gets its other common name.

Our breeding birds may winter as far away as Spain, while others visit us in winter from the continent. The movements are quite complex and difficult to decipher on the ground, but computer analysis helps us to make sense of the records. The autumn migration is leisurely and large – leisurely because the urge to find a territory and mate is no longer present, and large because of the presence of the young of the year.

The period between the spring and autumn peaks is slightly less than five months. One of these months is spent reaching the breeding area, and another in returning. The intervening time is taken up in rearing the young.

More interesting are the figures for record size. The average clutch size in the lapwing is four, and mortality among the young is about fifty per cent, so that, for every two lapwings passing north in spring, roughly four can be expected to pass south in autumn. The computer shows that the autumn migration is indeed virtually twice the size of the spring one, although the picture is complicated by the presence of non-breeding birds and the early arrival of winter visitors.

Migrating lapwings bring with them a sense of adventure, of viatic excitement and, in the autumn at least, give an overwhelming impression of lassitude. For the adults, the great labour is over for another season. For the young, the vastness of their trek is just becoming apparent. They are like an army in retreat.

In this area, the valley of the Colne is the lapwings' chief highway. Loose-winged, shabby and moulting, they pitch in straggling flocks, breaking for food and rest in traditional places where they know they have a chance of remaining undisturbed.

There are about a dozen favoured sanctuaries along the valley. Later in the season, large numbers will congregate on the stubble by the main road, within yards of the traffic. Against the sun they are hardly visible: not one driver in a hundred knows they are there.

At this time, though, the birds prefer to keep even closer to water. On the sloping pastures near Hampermill, hidden among the gravel strands and islands at Stocker's Lake, on the wide lawns at the Maple Cross sewage works, or here beside the glittering water of Moorhall Gravel Pit, they doze with heads on backs, preen, or pick desultorily at a spider, worm, or insect in the turf.

A hundred yards or more of water lie between you and the birds. Seated on the grassy bank of the causeway between Moorhall and the much larger Broadwater at your back, you are studying the flock and trying to count the number of adult and juvenile birds.

There is a class of bird-watchers, called "twitchers", who seek only to add sightings of rare species to their checklists; ornithology is not a matter of train-spotting, although every bird-watcher is pleased and excited if something unusual comes his way. No: it is a matter of coming to know the birds and their places with an intimacy that allows you to share, if only slightly, in their lives. To know where these lapwings are from and what they are doing here is a pleasure a hundred times more rewarding than adding yet another name to a list.

There is a complacent satisfaction too to be had from living in the same district for a long period of time. Only in this way can you experience the subtler pleasures of bird-watching – such as a true appreciation of this June afternoon at the gravel pits when compared with all the cold, damp, or blustery days of the winter.

The lapwings are spread out along the ragwort-dotted pasture, among a grazing flock of Canada and grey lag geese. Those not feeding look numb with fatigue, torn between the urge to rest and the urge to travel on.

From here their upperparts do not seem black at all, but a bronzy brown. The edges of the wing feathers especially are paler, almost cream-coloured, where they are abraded and worn.

The birds are almost all facing north-east, into the breeze, but, since many of them are feeding and the geese are also moving about, an accurate count as yet has been impossible.

And now it is too late. Two trespassing boys have just ducked through the barbed wire fence. The flock takes wing: black and white now, in wavering formation, there are still too many to count. Perhaps a hundred and twenty.

They turn west, rising against the trees. By now they are above the main road, above the glass and metal and the roar of the traffic and, with a few scarce, reedy cries of joy, are beyond the old Denham film studios and again on their way south.

The Aquatic Ape?

Even here, lying on a towel in the sunshine by the swimming pool, there is plenty to occupy the student of natural history. For the final focus of the naturalist must be his own species, _Homo sapiens_ , the animal that has inherited the Earth.

The planet has been waiting for this creature for over 4500 million years. There was a false start: the age of dinosaurs would probably, in time, have produced a two-legged lizard with the power to classify and manipulate its environment. But the age of dinosaurs was cut short, perhaps by the crash of a gigantic meteorite causing a centuries-long chill that the reptiles could not endure. The cold would favour one of evolution's newer experiments, the warm-blooded mammals.

At that time the mammals were primitive, nondescript, tiny animals, unlikely forerunners of the final inheritor of the kingdom.

Even during the next tens of millions of years no real candidate seemed to be emerging. The most advanced of the ancestral apes so far discovered was a primate called _Ramapithecus_. The next most advanced primate we know of is _Australopithecus_ , a man-like ape that is believed to be a forerunner of the genus _Homo_ , which of course includes modern man.

Between _Ramapithecus_ and _Australopithecus_ there is a huge leap in potential. We owe our position in the scheme of things to a number of factors, two of which are of supreme importance. The first is the ability to walk on two legs rather than four, freeing our forelimbs for manipulation of tools. The second, eclipsing all else, is the power of speech.

Speech requires language, which is the ability to classify. This ability gives rise to abstract thought, logic, foresight, and the handing on of knowledge to succeeding generations. With the invention of writing, speech can be preserved indefinitely. Writing gives rise to science, to mastery of the environment.

So how and where did this leap take place? No one yet knows for sure, but clues might be here today, at the swimming pool.

Why is it that human beings are drawn so much to water? Other modern primates – the chimpanzee or gorilla, say – are generally afraid of water and will do anything to avoid swimming. Yet, at every available opportunity, it seems that _Homo sapiens_ takes his family off to the beach. If he cannot get to a beach he will go to a specially constructed waterhole instead, like this one.

Observe if you will the infants in the shallow end. There is a baby with its mother, too tiny even to sit up on its own, gurgling and splashing as if water were its natural habitat. Observe also the other adult humans who, like yourself, are sunbathing between swims.

They are without fur; they have (some more than others) a layer of fat under the skin; and if you look closely, you will see that they have the vestiges of webbing between their fingers and toes. All of these are uniquely the characteristics associated with aquatic mammals such as the whale or dolphin. None of them is to be found in any other living primate.

Several of the sunbathers are overheating and beginning to sweat. The possession of abundant sweat-glands has been described by one professor of dermatology as a "major biological blunder", costing the human animal vast amounts of precious water and depleting the system of essential salts. Strange that in a creature so perfectly fashioned there should be such an evolutionary mistake – assuming, of course, that man evolved entirely on dry land.

Notice again the mother and baby in the shallow end. The mother is walking about on the bottom, holding her baby on the surface. The same technique of wading is used by primitive fishermen, enabling them to exploit food supplies denied to land-bound animals.

As yet there has been no fossil evidence to support it, but some zoologists have put forward the idea that the seeds of the genus Homo were sown some time between 9 and 3.7 million years ago, when a huge area of East Africa became flooded. Populations of forest apes were marooned and had to adapt or die out.

Man's pelvis, unlike that of other modern primates, is angled so that, when stretched out in the water, he is able to swim "in line", exactly like a penguin or dolphin.

Another feature that man shares with aquatic animals is the "diving reflex", in which the heart rate slows down during diving, reducing oxygen consumption. Expert pearl divers can remain submerged for up to 3 minutes and reach a depth of 262 feet, during which their heart rate falls by about 50%. The diving reflex is usually found together with a marked improvement in breath control – and breath control is one of the essentials of speech.

The colonization of a new medium, water, requires the acquisition of a whole new set of locomotor skills: swimming, diving, an acute sense of balance and direction. An increased locomotor repertoire, as it is called, leads to an increased brain capacity, a phenomenon that is plainly to be seen among the highly intelligent whales and dolphins. These animals, incidentally, also have superb breath control and a complex system of calls that might, if we could only understand it, turn out to be a language of abstract as well as concrete ideas.

When the floods receded, the mooted semi-aquatic ape then had to adapt all over again, enlarging its locomotor repertoire still more. Already adapted to going on two legs, the advantages of this method of walking encouraged evolution to refine and perfect the systems that make it possible. From the region of the flood the apes gradually migrated, spreading out along the Rift Valley, which is where the remains of _Australopithecus_ were found.

From _Australopithecus_ to _Homo sapiens_ is quite a jump: from the Tiger Moth to the Space Shuttle. But that is nothing like the earlier jump that had to be made to give man his unique set of advantages. It is a fascinating subject to speculate on; and fascinating to wonder whether echoes of the aquatic lifestyle of our remote ancestors live on today, here in the blue waters of Bushey baths.

But that's quite enough theory for now. I think I'm going in for another dip. Coming?

Nettles

Near the abandoned watercress beds, within a few yards of the stream, the ruins of an old cottage adjoin the footpath. The rubble is overgrown with stinging nettles, which protect the precincts of the cottage from intrusion.

By the middle of July the nettles have reached their greatest height. They grow here so well because the soil is rich in nitrogen – bequeathed by the middens and latrines of the former occupants. The plants are getting old and tough now, and even more uncompromising than they were in the spring. A bed of "stingers" is agony to walk through with bare legs and arms, and usually receives a punitory slashing from the countryman's stick.

Is this punishment deserved? The nettle, after all, is only protecting its own, and uses the same irritant, formic acid, that is found in ants' stings. Both weapons have the same purpose – to repel invaders.

The nettle's stinging organ is simple but effective, a modified hair, long and hollow and with a swollen base into which the acid is secreted. The point of the sting is formed by a very sharp, very thin scale of silica (the basic ingredient of sand or glass). The scale is so sharp that even the slightest contact causes it to break off in the skin, making a tiny wound, and the acid is then squirted into the wound by contraction of the base, rather as in a hypodermic syringe.

If the plant is wilting, dried, or cooked, the mechanism will not work; and if you "grasp the nettle" you will not be so much stung, for many of the hairs will be bent or crushed before they have a chance to act.

The sting was probably evolved as protection from the browsing lips and tongues of deer and wild cattle, for the nettle was originally a plant of lightly shaded woodland and clearings. It is dioecious (having "two houses"), which means that the straggly catkins of male and female flowers are found on separate plants. The male flower has four stamens, each bearing a pollen-laden anther at its tip. The stamens are sharply bent inwards to the centre of the flower, being released like catapults to send their pollen dust drifting on the wind.

The flowers are rather reminiscent of those of the cannabis plant, and inside a big nettle bed, especially after a long spell of dry weather, the smell is distinctly redolent of the forbidden weed – which is not to be wondered at, because the two plants belong to closely related families.

Like cannabis, which provides the hemp fibres still used in making rope, the nettle also yields fibres that can be woven; at one time in Europe, especially in Scandinavia, nettles were widely used for this purpose. Fragments of nettle cloth have been found in a Bronze Age grave in Denmark, and cloth was produced commercially in Silesia as late as 1920. Indeed the Germans, during World War I, turned to the nettle when their cotton supply was cut off, and used it for making military clothing. Over two thousand tons of fresh plants were taken from the wild, although it needed nearly ninety pounds to make just one shirt!

Nettle makes an unexpectedly good fabric, strong and light and fine, and a nineteenth century Scottish poet, Thomas Campbell, writes of sleeping in nettle sheets and dining from a nettle tablecloth. The stalks are picked in late summer, dried, stacked, and then wetted so that they begin to rot. Next they are dried again, and beaten to remove the rotten tissue from the fibres. The fibres can then be spun into thread, like flax or cotton (though nettle fibres are not so long), and woven in the ordinary way.

The commercial growing of nettles in England in medieval times is perhaps echoed in such place-names as Nettlebed (near Henley-on-Thames) or Nettleden, near Hemel Hempstead.

Besides the cloth, nettles will make the dye, provided it is fixed with the right mordant, alum. Admittedly the colour is rather a dull green, but it was this very quality that led to our use of nettles in the Second World War. We used hundreds of tons of them for dyeing camouflage nets.

They also provided a ready source of chlorophyll. The nettle is rich besides in calcium, potassium, iron, sulphur, and vitamins A and C. The young shoots, which do not sting, can be eaten in spring as a salad or cooked like spinach and served with butter and pepper. When dried, they make a herbal tea. A year or two ago I experimented with some wild herbal teas, and although most were pretty disgusting, the nettle tea I could at least drink more than once. It had a delicate aroma and was curiously warming, like a glass of brandy. When added in small quantity to an oriental tea, the nettle imparts a most unusual and exotic flavour that is well worth sampling.

Nettles figure in a number of herbal beauty formulae. An infusion of young or dried leaves is supposed to make a very good skin toner and an astringent bath additive.

It is as a medicinal herb, though, that the nettle really comes into its own, and has been used, with greater or lesser success, in recipes to treat a wide range of maladies, including bronchitis, whooping cough, pleurisy, and other chest complaints; diabetes, dropsy, gout, rheumatism, varicose veins, menstrual problems, diarrhoea, constipation (yes, both!), stomach ulcers, and piles.

Some of these cures are undoubtedly effective in some cases, and the nettle was a highly prized addition to the pharmacopoeia in former times.

In return for all this bounty, our ancestors were able to forgive the nettle its sting. Next time we pass this ruined cottage by the stream and feel like wielding the big stick, perhaps we should do the same.

Preening

The old stone bird-bath is much weathered now, cracked by past frosts, and in places its square, layered pedestal has become encrusted with grey and yellow lichen. It stands at a point in the garden a fair distance from the house, in the middle of a quartet of rose-beds virtually surrounded by yew hedges. On three sides there are trees of varying sorts and ages, some quite large.

Human disturbance is minimal; there is no dog in the household, and the only cats are occasional and unwelcome visitors from neighbouring gardens, so the place is a haven for birds. Kept topped up daily with the watering-can, a bird-bath provides a focal point for the garden and an endless source of movement and interest.

The most compulsive bathers are starlings, which create a tremendous amount of spray as they attack the water with their wings. Just now, in mid July, the greyish-brown juvenile starlings are especially numerous, and crowds of them are all trying to get into the water at once, leaving the less pushy dunnocks and song thrushes waiting on the grass near by.

From time to time, when the starlings permit, almost all the birds in the garden will come down to drink or bathe, and this is often the best chance to get a view of shy or otherwise hard-to-see species. This afternoon a blackcap has been down, as well as a willow warbler and, earlier, a great spotted woodpecker.

They expose themselves to view because they must. Bathing for these birds is essential to maintaining the plumage in good order. Its function is not primarily one of cleansing, but of preparing the feathers for what comes next. Indeed, most birds are careful to avoid getting their plumage drenched, because this eventually renders the feathers brittle and, more importantly, robs the bird of its power of flight.

The water-bath is a carefully controlled wetting, spreading an even layer of moisture over the feather surfaces. Having repeatedly ducked its head into the water and flicked spray over its back, the bird performs special shaking movements to rid itself of surplus water. The exact pattern of these movements varies from group to group; some birds, such as gulls, can shake their feathers even while flying.

A bird like the blue tit is typical of the garden bathers. Immediately it has finished at the water, it retires to a less exposed position in order to preen in safety.

The great majority of birds have a special gland just above the root of the tail. The gland secretes oil that keeps the feathers supple and waterproof. Preen oil has another function too. Birds, like humans, cannot synthesize vitamin D inside their bodies. We manufacture it in our skin, provided we are exposed to the sun. Vitamin D synthesis likewise takes place in the oil; the vitamin is then either absorbed through the skin or ingested by the bird while preening.

The first act of preening is to stimulate the oil gland with the bill; oil is then quickly transferred to the plumage with quivering and stroking movements. The bird must work fairly rapidly because the oil hardens on exposure to air. The fact that the feathers are damp delays the hardening and enables the oil to be spread more evenly.

Having made a quick distribution of the oil, our blue tit, as soon as it has the opportunity, moves on to the next, longer and more leisurely, phase of preening. The outer feathers are ruffled up, to make them easier to get at, and each area receives its share of meticulous attention. A bird's plumage is one of its most important assets, and much time each day is devoted to its care, both in these special sessions and during any odd moment.

There are two main types of preening movement. With the bill closed the bird sleeks down disarranged feathers and flicks away foreign particles. With it open, individual feathers – especially those of the wings and tail – are lightly combed.

The structure of a feather is a miracle of design. A large flight feather consists of a central shaft fringed on each side with about a hundred filaments, each of which, in turn, is fringed with smaller filaments or barbules. Each barbule has several hundred minute hooks that interlock with neighbouring barbules; there may be a million such hooks in a single feather. The combing action helps to restore the interlocking pattern and produce once more a smooth and continuous vane for flight.

Besides preening, birds in the garden may be seen maintaining their feathers in other ways. A favourite pursuit, especially of thrushes and blackbirds, is sunning. The bird, feathers ruffled and wings drooped, squats with its back to the sun, apparently just enjoying the heat: but the light helps to disturb parasites among the feathers, and makes them come out into the open where the bird can preen them away. A more extreme sunning posture has the bird sprawled with one wing fanned out towards the sun, its body tilted sideways and the tail swung round to the same side.

Dust-bathing is also indulged in by some birds, including sparrows and wrens. Its purpose is not clear, but may also have something to do with discouraging skin parasites. The same is true of the strangest feather-maintenance practice of all, anting.

In this the bird puts ants among its feathers, or simply squats over an ants' nest, allowing the ants to crawl into its plumage. It is thought that the exudations of the ants, like preen oil, help to keep the feathers in good condition. The type of ant usually chosen secretes formic acid when it is angry, which certainly acts as an insecticide, and the ants themselves may attack any parasites they come across. Hundreds of species of perching birds have been observed anting, but starlings, crows, and especially jays, are particularly addicted to it.

In fact there are starlings on the lawn at this moment, taking ants from a nest halfway down the path.

This is the kind of ornithology anyone can study, whether from a window or a deckchair. All you need is a sharp pair of eyes – and a bird-bath. It need not be elaborate; an old dustbin lid will do, as long as it provides a shallow gradient and its site a measure of seclusion.

Lichens

The tenacity of living things sometimes surpasses belief. There is scarcely a square mile of the planet surface, no matter how forbidding, which does not support at least some form of life. The richness and diversity of living systems reach their astounding zenith in the tropical rain forests; their nadir is at the polar icecaps, especially that of the south.

Even in the polar wildernesses of rock and scree, and even, in places, in the ice itself, life may yet be found. The forms here are usually quite simple, single-celled animals and plants. Where conditions relent slightly, if only for an hour or two a day at midsummer, the terrain is colonized by lichens.

In fact, over great tracts of the world's most inhospitable regions, lichens are the only multicellular organisms able to thrive. They grow abundantly in such daunting places as rocks that are alternately washed by the sea and baked by the sun. They will grow on walls, roofs, tree-trunks, on the bare soil. Some sorts even secrete acids that enable them to grow _inside_ rocks, waiting for the surface to weather away before fruiting.

The key to their success is as strange as it is wonderful, and may be studied here in suburban Hertfordshire as well as in Antarctica or the Sahara desert.

Though given a single scientific name, a lichen is really a partnership of two separate sorts of organisms – a fungus and an alga. Fungi do not have chlorophyll, and so cannot use photosynthesis to manufacture their own food, as green plants (including the algae) do. On the other hand, most algae cannot, unaided, survive extreme conditions. By entering into partnership, the fungus receives sugars and vitamins from the alga, while the alga in turn gets minerals and protection from extremes of dryness and illumination; and both organisms are then enabled to colonize places previously out of bounds.

A handful of the familiar mushroom-type fungi undergo lichenization, as the process is called, but the vast majority belong to a more primitive group, the _Ascomycetes_.

So specialized have these lichen-fungi become that few are now able to survive for long without an algal partner. The algae, however, especially if conditions are favourable, can often exist independently. Free algae of the right sort must be available for the formation of a new lichen by sexual reproduction, for it is the fungal element alone that produces spores. The fungus is the senior partner, makes up the bulk of the lichen's structure, and gives the lichen-plant or thallus its characteristic shape; the thallus usually has one of three main types of form: shrubby, leafy, or crust-shaped.

The clustered thalli can appear quite fantastic, like creatures from another world, or the vegetation dreamed up by an artistic imagination on the verge of madness, and the colours, which are always marvellously subtle and soft, come from Nature's most ethereal paintbox. At different seasons and in different states of dryness the appearance may change dramatically, for during adverse conditions the lichen "shuts down" and waits for things to get better.

Unless conditions are exceptionally favourable, most reproduction is by vegetative, or non-sexual, means. Many sorts produce little powder-dusted pores that also help to keep the thallus aerated; the particles of powder are called soredia, each of which, when dispersed by the wind or by sticking to animals and birds, can grow into a new thallus. Even simpler and more common is dispersal by fragmentation: bits of the parent thallus get broken off, for example by being trampled, and blow away to develop elsewhere.

The pores in a lichen ensure that there is free flow of gases between the photosynthesizing algae and the outside world. Lichens are often efficient at absorbing whatever substances are in the environment, which has had dire consequences for those Lapps and Eskimoes who depend on caribou and reindeer for food.

One of the main components of the vegetation of the northern tundra is the Reindeer Moss, which, despite its name, is a lichen. It bulks large in the diet of the reindeer and caribou, and is the main source of carbohydrate in that particular food chain. Unfortunately, Reindeer Moss is exceptionally good at absorbing the radioactive fallout from atom-bomb tests that finds its way into the upper atmosphere and is then distributed all over the planet surface. High levels of radioactive caesium and strontium have accumulated in the bodies of the grazing animals, becoming even more concentrated in the bodies of the northern people.

So good are lichens at absorbing toxic substances that they have been used as indicators of atmospheric pollution. The lichen flora of, say, North Devon or rural Scotland is rich in species: 1400 in all have been recorded in the British Isles. But as you approach the industrial centres the number of species falls off rapidly, as does the luxuriance of growth of those that remain.

Our local lichen flora is badly impoverished, simply because the air here is so dirty. The main pollutant is sulphur dioxide, produced by the inefficient burning of fossil fuels. But others, in far smaller quantities, and even more dangerous, are contributing to the continuing decline in lichens: fluorides, heavy metals such as cadmium and lead, agricultural and garden fertilizers and pesticides, and a whole catalogue of other industrial wastes – the list is depressingly long.

Lichens may be regarded like the coal-miner's canary. We ignore their death at our peril. The few species that remain to us in south-west Hertfordshire survive mainly by growing on alkaline surfaces, such as walls, asbestos roofs, limestone paving, and concrete, which offset to some extent the acidity of the rain.

Yet the ability of the lichens to colonize inhospitable terrain is undiminished. By poisoning the atmosphere, we have altered the balances that have remained unchanged for millennia, and those types that have become adapted to them will die. But already there are new and – almost – sinister types of lichen emerging, able to thrive in the new conditions. One, the aptly named Pollution Lichen, was unknown in Europe before 1860. A recently published guide chillingly gives its status thus: _Widespread in industrial and densely populated parts of Europe. Abundant in England._

The writing, in lichen lettering for anyone to see, is on the wall.

Balsams

Much is achieved by specialization in the study of natural history, but a more open and discursive approach is often more enjoyable and can lead to some unexpected byways and, finally, to a deeper understanding of the subject as a whole. For one feature of the living world always holds pointers to another, and another, and so on, a chain of fascination and discovery without end.

The first link in the chain is usually forged lightly enough, with an idle speculation. On a walk through Cassiobury Park, for example, an unusual, weedy-looking plant may be found at this time of year. It grows abundantly in the gloomy woodland near the canal and River Gade in the southern end of the park, especially by the paths in the vicinity of the commercial watercress-beds.

With small yellow flowers and large, toothed leaves rather like those of the Dog's Mercury, this plant is the Small Balsam, a close relative of the Busy Lizzie that makes such an easy and attractive pot-plant. It is a native of Siberia and Turkestan, and was introduced to this country in the last century, having first been found growing wild here at Battersea in 1851.

In Hertfordshire it occurs mainly in the vicinity of certain towns, including Hemel Hempstead and Watford. Its distribution in the county can be understood when it is known that one of its favourite habitats is timber yards and that seeds were presumably imported in the 19th century as stowaways in consignments of exotic timber from the east. The presence of Small Balsam in the Gade Valley may not be unconnected with the Corner Hall Wharf at Hemel Hempstead of W H Lavers & Sons, the well known local timber merchants.

Having been inadvertently introduced, the Small Balsam spread out as far as it could, being checked only by its own needs for moisture and shade. Most balsams are a bit like this, never being found far from water or damp ground. The Busy Lizzie likewise needs plenty of water to keep healthy.

A second alien balsam, the Orange Balsam or Jewel-weed, is also found in Cassiobury Park, as well as elsewhere along the line of the Grand Union Canal. In fact, a map of its distribution in Hertfordshire is tantamount to a map of the course of the canal. A larger, more handsome plant, with orange flowers spotted with crimson, the Jewel-weed got here from eastern North America as a garden introduction, first turning up in the wild in Surrey in 1822. It is now locally common along most of the waterways of the Thames basin and is apparently still on the increase.

Yet a third alien balsam, the Himalayan Balsam, variously known as "Policeman's Helmet" (from the shape of the flowers), "Jumping Jack" (from its explosive seed dispersal mechanism), or "Nuns" (for no discernible reason!) can be found in the park. A big clump grows beside the third bridge over the Gade (counting downstream), adjoining the most luxuriant growth of the Small Balsam.

Policeman's Helmet is an even showier plant than the Jewel-weed. It can reach a height of six feet or so, has thick and often reddish stems, and large flowers in every shade of purplish-pink. Again it was introduced in the 19th century as a garden plant, a native of India and the Himalaya, and was cultivated at first as a greenhouse annual. It soon escaped from captivity and by 1855 was to be found spreading rapidly along waterways.

Now these three foreign balsams illustrate a number of the laws by which nature seems to govern her affairs. The vigour with which they have taken over our waterways shows how alien genetic stock, freed from the competition at home, can have an unfair advantage over the home-grown organisms – for it is the same with fauna as with flora. The native stock has not had time to evolve defences against them: the checks and balances built up over tens of thousands of years no longer have any meaning.

The only native balsam, the Touch-me-not, is, in plant terms, something of a failure. It puts forth its flowers in damp woods in north-west England and north Wales, being very local even where it is found. It cannot compete effectively. Man's mistreatment of the environment is going hard with it, while its foreign cousins are actually taking advantage of man and his activities.

The four British balsams, one native and three introduced, are all closely related and are obviously descended quite recently from a common ancestor. In size, though, they show a clear differentiation. Each species occupies a slightly different niche, has a slightly different role to play: this is how new species evolve. They rarely trespass on each other's terrain. The Small Balsam, for example, is pollinated by hoverflies, the Touch-me-not by bees, and the Policeman's Helmet by bumblebees. As for the Jewel-weed, it may dispense with pollination altogether, its flowers often all being of a type known as "cleistogamous".

Cleistogamy (literally, "closed marriage") is an unusual and somewhat degenerate response to the heavy cost of producing flowers as a means of reproduction. Cleistogamous flowers are of simplified form, with few pollen grains, and automatically self-pollinate at the bud stage. Among our group of balsams there is a pretty smooth gradation in this habit, from the Policeman's Helmet, in which it is unknown, through the Small Balsam and Touch-me-not, in which increasing numbers of cleistogamous flowers are found, to the Jewel-weed, in which cleistogamy has assumed major importance.

A study of cleistogamy in these four plants would lead us deeper and deeper into the realms of genetics and evolution. A study of their habitat preferences draws us into the fields of plant physiology, ecology, and climatology. A study of their origins takes us to the history of human trade and commerce, 19th century tastes in timber and veneer, the exploitation of Russian and Asian forests to meet those demands ...

And so it goes. Many, if not all, the scientific investigations ever undertaken have had just such trivial beginnings as a stroll through the local park and an idle question like: "What's the name of that plant?"

Dragonflies

The dragonfly is the heraldic emblem of these August afternoons. It is a creature of the heat, its darting activity and purposefulness a direct contrast to the lethargy that overtakes the canal, the river, the weed-choked ponds and streams. Its colouring belongs more to the tropics than to the English lowlands; and in its ferocity the dragonfly reminds us of the merciless insect-war going on, mostly unseen, everywhere in the dense vegetation of summer at its height.

Throughout the whole animal kingdom, indeed, there are no more brilliant colours than those of certain dragonflies. Insect colours are produced in various ways and for various reasons. Some pigments are mere by-products of other bodily processes, with no special significance, but most have some function, however obscure.

The bright yellow laid down in the cuticle of, say, wasps or bees, gives notice that the animal is not to be trifled with. Reds and oranges often signify that the owner is unpleasant to eat. Many other colours and patterns are important in camouflage, courtship, mating, or the defence of territory.

In some insects, colours are produced by intricate structural effects as well as by simple pigments. Iridescence in the more dazzling hues of many butterflies, and the metallic bronzes and greens of beetles, for example, results from an interference effect – involving the reflection of certain wavelengths of light from successive layers in the insect's scales or cuticle. These colours are brilliant enough, but the dragonflies have gone one stage further.

Besides having a wide complement of pigments, they make use of a phenomenon called Tyndall scattering. In this, light is dispersed in all directions by irregularities in the cuticle surface or by granules laid down just beneath it. The size of the irregularities or granules is minutely adjusted to the wavelength of the light that is to be reflected.

Tyndall scattering is responsible for the incandescent blues and greens of many of our dragonflies. It depends for its success on a dark masking layer below the granules, provided by a brown-violet pigment, an ommochrome.

Ommochromes are widespread in insects. As well as providing brown, red, and yellow body-colours, they have a more specialized use as masking pigments in vision, isolating the individual elements of the compound eyes and enabling them to function.

This leads us to another remarkable feature of the dragonfly's life, the refinement of its eyesight. Dragonflies are normally day-flying insects. They rely almost entirely on their eyes: the antennae, the seat of taste and smell, are poorly developed. In some insects the compound eyes may contain only a few widely spaced elements; in the dragonfly there may be ten thousand or more in each eye, closely packed together in a hexagonal formation.

Each element in the compound eye sends a signal to the brain, forming a sort of mosaic image. Compared with the human eye, focusing ability and acuity are not very impressive, but the dragonfly's eye is supremely well adapted to detecting movement. There is very rapid recovery of bleached visual pigments, a high so-called "flicker rate", enabling the animal to make sense of the landscape as it races past, and enabling it to see and catch its prey with lightning speed.

The prey consists mainly of flying insects, sometimes other dragonflies. It is caught with either the jaws or legs. The legs are found well forward on the thorax, which is itself tilted in such a way that they form a basket to scoop an insect from the air and hold it steady while the mouthparts are brought into action.

There are two sub-orders of dragonflies. The first contains the damsel-flies, and the second the larger, more powerful dragonflies such as the fearsomely named _Anax imperator_. The eyes in this second group reach an astounding peak of size and development, covering most of the surface of the head.
Much time is expended by the insect in cleaning the eyes with special movements of the forelegs. The head is balanced on a delicate suspension mechanism that allows it to swivel, giving all round vision. So delicate is this mechanism that if the dragonfly hits head-on even a lightweight obstruction – such as the folds of a collector's net – irreparable damage will be done.

Set beside the technical achievement of constructing just one dragonfly, human efforts to date in the fields of cybernetics and microelectronics look distinctly clumsy. To be fair, the craft of dragonfly-making has had some three hundred million years in which to be perfected: the dragonflies were among the first of the insects to evolve.

The individual adult dragonfly also has a long time in which to develop. Most of a dragonfly's life is spent underwater, as a nymph, a fierce carnivore that repeatedly moults its skin as it grows in size. There may be a dozen moults in all, and the underwater period varies from one year in the damselflies to a dozen in the largest species. When the time comes for the final moult – usually in June or July – the nymph crawls up a plant-stem, often during the early hours and, with frequent pauses for rest, breaks out of first one part of the skin and then another.

By dawn the newly emerged, or teneral, dragonfly resembles a mature adult in all respects except for its pale colouring and the flaccidity of its wings and body. As the sun rises the wings harden and become ready for flight. The cuticle hardens also, and within a few hours the insect is ready to fly: the colours develop over a period of days.

In the few weeks of life remaining to it the dragonfly must mate. Females are actively sought out by the males, which frequently are strongly territorial, maintaining one stretch of water as their exclusive property. The eggs are laid in vegetation, or simply scattered in the water to sink to the bottom.

With the first frosts the remaining adults are ruthlessly cut down. Together with hundreds of millions of other insects, they have betrayed themselves by leaving eggs to perpetuate the race. They are no longer required. Thus does Nature treat the most intricate fruits of its creation: and thus vanishes the magical dragonfly, emblem of this brief English summer.

Spotted Flycatchers

A new little bird appeared yesterday morning at the corner of the road, perching on a telephone wire high above the pavement. It first attracted attention by its call – a characteristic _wee tuc-tucc, wee tuc_ that, once heard and learned, is never forgotten.

The owner of this cry is just the sort of small brown bird to puzzle the beginner, with mousy plumage above, paler underparts and a few dark streaks on the breast. But its upright, watchful posture and, above all, its behaviour, confirmed the identification at once.

From its perch on the wire the bird made repeated swooping sallies at flying insects, swerving in mid air to return to the same spot. After a short rest it ventured forth again, returning this time to a bare twig in one of the trees that line the road here.

Gilbert White, in his letter to Thomas Pennant of 4 August 1767, says: "The _stoparola_ of Ray (for which we have as yet no name in these parts) is called, in your Zoology, the fly-catcher. There is one circumstance characteristic of this bird, which seems to have escaped observation; and that is, it takes its stand on the top of some stake or post, from whence it springs forth on its prey, catching a fly in the air, and hardly ever touching the ground, but returning still to the same stand for many times together."

The good curate of Farringdon, in Hampshire, was as precise in this as in all the observations contained in his _Natural History of Selborne_ : the bird on the corner was indeed a fly-catcher: a spotted flycatcher, to be exact, the _Muscicapa striata_ of our zoology.

It was still present this afternoon, although it had moved a few yards along the road. It is on its way to Africa for the winter and, as flycatchers do, has taken a sudden and unaccountable liking to this place.

The preference of the flycatcher for one location over another is something of an enigma. On the one hand the bird tolerates man, often building its nest close to a busy path; on the other it seems attracted by the tranquillity of an unfrequented garden or woodland clearing.

One pair that nested in a small copse adjoining the school swimming bath were, with their fledglings, much in evidence when no one was about, perching now on the close-boarded fence by the grass, now on the diamond-mesh fence running from the changing shed to the filter house. The sound of the filters, the smooth surface of the deserted pool, the blue reflections and refractions, the dense foliage of the oaks and lindens of the copse: all this gave the place an air of magical seclusion of which the flycatchers seemed to form a natural part.

They were brought here by the many insects attracted to the water. Even when the flycatchers' domain was invaded by a solitary swimmer they continued to feed. But as soon as more people arrived, the birds withdrew, emerging again only later when peace resumed.

Flycatchers are like this in gardens too. Best of all is a garden untenanted, overgrown, with plenty of neglected corners to bring the insects and a sufficiency of bare twigs for feeding-perches. Next best is a garden frequented, if at all, only by one or two gentle souls with trugs and secateurs. The passage flycatchers appear at hedge-clipping time. They do not object to the click of hand-shears, but vanish at the whine and rattle of electric cutters, or at the noise of all the other mechanical abominations with which even the smallest garden now abounds.

Yet the spotted flycatcher is one of the few species – the others are the chaffinch, great and blue tits, song thrush, blackbird, dunnock, and wren – that can thrive in the gardens of Inner London. They are able to do this because their requirements for food and nest-sites are comparatively unaffected by lack of undergrowth. Flies may be found almost everywhere, and their catchers are content to nest on a beam or branch close to a wall or tree trunk, or in a crevice in masonry. Thus flycatchers are among the few species able to breed in the Royal Parks or in the squares of Mayfair or Bloomsbury.

There is another sort of breeding British flycatcher, the pied flycatcher, with a more westerly distribution. This bird has been seen in the district only on a handful of occasions, usually on autumn passage. The spotted and the pied are typical of the flycatchers found in Europe, with flat, rather broad bills surrounded by bristles that help direct the prey into the gape.

Elsewhere in the world, especially in the tropics, there is a large and diverse array of birds of the flycatcher tribe. Some are brilliantly coloured, as small as wrens or as large as thrushes; many have habits nothing like those of our own native species. In New Guinea, for example, many of the fifty or so breeding species behave more like warblers, chats, or even shrikes than flycatchers. In Madagascar live species that live sociably in the tree canopy, just like our native blue tits and great tits. In south-east Asia are flycatchers that keep to the shadows of the undergrowth, like our robin.

But they all share a certain special elegance and grace, and give a peculiar impression of rightness in their habits and form. The flycatcher on the corner, by choosing this place for his halt on the journey south, has, in his own small way, conferred on it the accolade of his approval and made it better than it was before.

Probably he will be there tomorrow too, but the following day he may well be gone, leaving behind a sense of flatness, emptiness, and loss: a sense of impending autumn.

The Moon

The full moon of August will be with us tomorrow. In one ceremony of ancient Japan this moon, seen reflected in water, symbolized more than anything else the mystery and transience of life. But to see the Moon at any time, and at any phase, can be an awe-inspiring experience. Whether you are in the comfortable north-western suburbs of London or camped out on an Antarctic ice-floe, the Moon presents the same inscrutable visage.

It is a true wilderness, remote, aloof from our concerns and, except for the assorted junk left behind by space programmes, as yet unbefouled.

The familiar pattern on the Moon (representing a man's face, a hare, a beetle, the Madonna and Child, or a dozen others, depending on your culture) is made up of the darkness of plains contrasted with the brightness of mountains. Seen with binoculars, the pattern disappears at once, and it is only then, with the Moon filling your field of view, that you get some idea of its majesty and size.

For, although the Moon is held to be a mere satellite of the Earth, it is much bigger than the moons of Mars or Jupiter, being over one fifth the weight of the planet Mercury. Indeed, according to one theory of the Moon's origin, it was once a small planet, with an independent orbit.

This theory suggests that, at some time at least four billion years ago, the Moon passed sufficiently close to the Earth to be "captured" by the Earth's gravitational field. As the Moon passed there would have been huge tides, miles high, in the Earth's oceans. The energy to produce these tides was thus transferred from the Moon to the Earth, slowing the Moon down and preventing it from getting away.

There is a theoretical limit at which any satellite can remain intact, called the Roche limit, that, in the case of Earth, is about 3700 miles from the planet surface. Once the Moon reached the Roche limit it began to break up, losing half its mass to the Earth, especially the heavier rocks containing iron. This material became the present continental land masses.

The remnants, now just outside the Roche limit, gradually reformed into a sphere and began to retreat, towards the Moon's present mean distance of almost 240,000 miles from the Earth.

An older theory was that the Moon was originally torn from the substance of the Earth, leaving behind the scar that we now call the Pacific Ocean. Recent understanding of the way continents drift makes this idea seem less likely, as does the fact that rock samples brought back by the Apollo missions prove that the geology of the Moon is very different from that of the Earth.

All the planets in our solar system, and their satellites, were formed by clouds of gas from the Sun, but not all were formed at the same time or from the same cloud. Another theory of the Moon's origin is that the Moon has always been in the Earth's orbit, but was formed from a different cloud. Of the three theories, the first is perhaps the most favoured today. Since we do not yet even know in detail how the Earth was made, it may be premature to expect firmer knowledge just yet.

These are matters for the physicists and mathematicians to ponder. But it requires no special knowledge to look at the Moon, and if you have even an old pair of opera glasses you can follow in the tradition set by Galileo, who first turned a telescope on the Moon in 1610. Although he probably knew that no large expanses of water were to be found there, it was he who named the dark areas _maria_ (seas) and the light ones _terra_ (land).

These terms have survived to the present day, inappropriate as they are. We now know that the Moon's surface is almost unbelievably harsh. When Neil Armstrong took that "giant step for mankind" on 21 July 1969, he stepped into a desert of black, basaltic dust and rock, baked during full sunlight to the temperature of boiling water and frozen during the lunar night to the temperature of liquid air.

On the Moon there are mountains higher than the Himalayas and craters up to 180 miles across and 2600 feet deep. The atmosphere is extremely thin, for the Moon's gravity is only one sixth that of Earth. This means that there is almost nothing to protect the Moon from the impact of meteorites, the chunks of rock that, hurled out perhaps thousands of years before by some disintegrating star, travel on and on through empty space until they meet an obstruction. Most of those striking the Earth get burned up by friction with our thick atmosphere: not so on the Moon.

The surface of the Moon is buried to a depth of several feet in meteorite debris. Its entire surface is pockmarked with craters, from the microscopic to the gigantic. When the impact is especially great, splashes of moondust are thrown in all directions. These bright splashes are called "rays" and, until disturbed by further impacts, may clearly be seen from Earth.

One of the most perfect craters, as yet virtually undamaged by subsequent impacts, is Tycho. This is in the southern hemisphere, at about the same latitude as New Zealand is on Earth. The 54-mile wide crater has a sharp central peak and walls that rise to 16,000 feet.

The splashes radiating from Tycho have spread out across almost the entire visible face of the Moon, one ray even being seen to cross the Sea of Serenity in the northern hemisphere. The best views of the Moon are usually to be had at other phases, when the slanting sunlight makes the surface stand out in sharp relief, but full moon is the time to see the rays of Tycho.

The full moon – and what better than the August one, traditionally the moon to be viewed – is also, perhaps, the most impressive and the most suitable way of reminding ourselves of the true value and scale of things.

Black-headed Gulls

As summer comes to its close, the annual influx of gulls gathers pace. By autumn they are everywhere in the district, feeding on pasture and arable and parkland, by and on water of all kinds and, ever on the lookout for a meal, patrolling the skies above back gardens and industrial sites.

There are five common sorts that visit us here, and the commonest of these is the black-headed gull. This is the smallest and the slenderest of the five, and can be told by its red bill and legs, and the long white triangle on the leading edge of the wings, which have pointed rather than rounded tips.

Despite its name, the black-headed gull's head is not black. In spring and summer the adult has a chocolate-brown hood, which is moulted in autumn to leave the head pure white except for two dark smudges, the larger one behind the eye and the smaller one just in front of it. The immature bird is more mottled in appearance, but still has the white triangles on the wings and, at all seasons, the smudges on the head.

In grace, buoyancy, and agility of flight the black-headed gull has few equals among our winter birds. During autumn it makes a habit of following the plough, and a hundred or more at a time can be seen swirling like snowflakes against the freshly turned soil. The same sort of prey – wireworms, millipedes, earthworms, and so on – attracts it to football fields and similar grassland; but our local black-headed gulls find their shangri-la on pasture that has just been sprayed with Hydig, the fertilizing sludge produced at Maple Cross sewage works, just south of Rickmansworth.

The sewage works themselves are also an attraction for gulls. In the grounds is a disused gravel pit that, during the 1960s, was filled with solid matter rejected during the purification process. A long black outfall pipe led from the works into the middle of the pit. Some of the outfall consisted of sand, so that the pit slowly became silted up, but it also contained grain, as well as a comprehensive assortment of the things that get dropped or thrown into the lavatory (among them many children's toys such as rubber Donald Ducks, combs, nailbrushes, pairs of spectacles, and any number of sets of false teeth.)

Among all this detritus the gulls used to gather, picking over the spoils. At irregular intervals there came a distant rumbling in the pipe. At this the gulls' excitement mounted, and with expectant cries of _kwarr_ the flock drew closer to the broad mouth of the pipe, flying up when, with a rush, it disgorged a fresh supply of sludge.

During hard weather this was an important source of food for the gulls in the Colne Valley, and as many as 400 birds could be seen there at once. The dumping has finished now, but the sewage works still draw plenty of gulls. After detailed observation the same individuals can be recognized returning day after day, for some birds have peculiarities such as a deformity of the bill or an odd pattern of plumage. A few of the gulls carry aluminium leg-rings, put there by ornithologists perhaps in other countries.

One ring seen on a living bird bore the number C-17122 or C-1722. From this and a description of the pattern the British Trust for Ornithology were able to say that the ring was of Finnish origin, and in fact many of the black-headed gulls that winter with us breed in the countries round the Baltic Sea, especially Sweden and Denmark.

In Britain the black-headed gull breeds, especially in the north, on saltmarshes and sandhills close to the sea. Yet it is also the most inland of our gulls and nests on marshy islands in lakes and moorland pools far from the coast. In the early 1960s a few pairs even bred at Maple Cross, but the colony was soon abandoned.

It is difficult to imagine today that all gulls, even the black-headed, were once very rare in this area, being seen only when storms at the seaside blew them off course. Their success is attributable directly to man: they have learned to exploit the many opportunities, like the sewage outfall pipe, we have unwittingly put in their way.

The only problem for gulls inland is the need of a safe roost. The first gulls to appear in any numbers in London arrived in the bitterly cold winter of 1894-5, and they roosted then mainly on the Thames at Chiswick Eyot, or at the small Lonsdale Road Reservoirs.

At the turn of the century there was a big increase in reservoir-construction. The huge Staines Reservoir was completed in 1902 and quickly became a major gull roost. The other reservoirs in that part of Middlesex and north Surrey, some even bigger than Staines Reservoir, as well as a chain of reservoirs in the Lea Valley, provided further roosting. Today well in excess of 100,000 gulls roost in the London Area during winter.

When it was filled, in 1955, Hilfield Park Reservoir near Aldenham soon became an important roost, attracting something like 5,000 birds. Many of our local gulls roost there, and at dusk make their flight-lines in that direction. The rest of our birds roost, or did roost, at Staines, and the birds from the Colne Valley can be seen flying south at the end of day. This is where the Maple Cross birds roosted, arriving there 25 minutes after first light, having taken that time to fly, at 40 m.p.h., the distance from Staines.

But now these opportunists have found a way to cut their commuting time. A vast gravel pit, Broadwater, has been dug at Denham, large enough to make a safe roost, and many Staines-bound gulls have adopted it as their own.

A gull roost as it fills is an extraordinary sight. The sheer spectacle of so many birds in one place is not soon forgotten. To see them arriving, each with a different experience of the day's foraging, is a powerful reminder of the adaptability of living things and the effect that man has had on their world.

As the gulls come in, you tend to forget about their feeding habits and are conscious only of a sense of wonder and beauty. If only all our activities produced a result like that.

Aristocrat Butterflies

The fermenting juice of rotting windfalls brings many wasps and flies, the odd hornet and, with luck, butterflies. If near by there are also September flowers – especially Michaelmas daisies and buddleia blossom – the chance of butterflies is increased still more.

By this time of year the majority of butterflies still on the wing are those that spend the winter as adults, rather than as eggs or larvae or pupae. Typical of this group are certain members of the nymphalids, a family that contains some of the showiest and best-known British butterflies, such as the Peacock, the Red Admiral, the Comma, and the Small Tortoiseshell.

So entranced were the early lepidopterists by this family that they called many of its children the "aristocrats" and gave them names to match. The Purple Emperor, the White Admiral (the word Admiral is a corruption of "Admirable"), the Camberwell Beauty, and the Large Tortoiseshell are rare in England today. A frequent cause of a butterfly's decline is increasing scarcity of the plant or plants on which its caterpillar feeds. In the case of the Large Tortoiseshell, for example, the major food plant is elm; through Dutch elm disease, we have lost twenty-five million trees since 1970.

But not all is gloom. Many sorts of insects – a number of aristocrats among them – depend either partly or completely on the nettle for food and shelter. The nettle is highly nutritious for hungry caterpillars and, best of all, avoided by grazing animals. It is usually found in association with man, thrives on waste ground, and may be locally abundant.

The Red Admiral, the Peacock, the Small Tortoiseshell and the Comma are all partial or exclusive nettle-feeders, so it is no surprise that these are the aristocrats commonest today. The Comma – a tawny butterfly with its jagged-edged wings spotted with black – has in fact been increasing its numbers since about 1925, for reasons not fully understood.

The Comma gets its name from a small, comma-shaped mark in silvery white on the underside of each hind wing. The rest of the undersides are camouflaged with brown and darker brown pencillings, so cleverly that when a Comma closes its wings it can seem to disappear. Its caterpillar, which leads a solitary life, goes one better in the camouflage game and looks very much like a bird dropping. The adult butterfly is often seen in gardens, where it may form an attachment to a small area – sometimes of just a few yards square – with its own favourite leaves for resting and basking in the sun.

The Peacock and the Small Tortoiseshell also have drab, disguised underwings that contrast with the ostentatious patterns above. The Small Tortoiseshell, marked with orange, brown, contrasting patches of black and white, and with a tracery of tiny blue half-moons along each trailing edge, is perhaps the most familiar of the garden aristocrats.

The Peacock is almost as common. It is so called from its four large "eyes", the ones on the hind wings being especially like those on peacock's feathers. The colouring and texture of its wings are almost unbelievably subtle and complex, more inventive and in far better taste than even the most costly oriental carpet. However long you study a resting Peacock, always apprehensive that at any moment it will decide to flit away, your eye can never take it all in; the brain can remember no more than the crudest essentials of the pattern.

It is no answer to catch and kill the insect and pin it to a board, for then, with its life, its vibrancy is lost and the colours seem to fade. Butterflies must be admired in their totality, and that includes sunlight and air and the liberty to fly away.

The fruit-strewn turf of a neglected orchard is a fine place to see Red Admirals. Drunk on cider and greedy for more, they are more approachable than usual. The wing-pattern is predominantly black, with a scarlet band across each forewing, another on the trailing edge of each hind wing, all offset by white splashes and touches of azure. As it sips the sweet, intoxicating juice the butterfly continually opens and closes its wings as if in ecstasy. The scene is almost one of decadence. In places two or three Red Admirals jostle with Peacocks and wasps for the best places on the decaying fruit.

This taste for decay is reminiscent of some of the really big tropical butterflies that flock to putrefying carrion. At one time Purple Emperors were baited with dead rabbit; besides rotting fruit, the Red Admiral likes the rich sap oozing from damaged oak trunks.

The Red Admiral, like several other nymphalids worldwide, is a migrant. It arrives in May, having flown here from North Africa or Southern Europe, and lays its eggs, singly, on the upper surface of nettles or related plants. These eggs give rise to the resident summer generation; some of the butterflies feeding in the orchard may be on a return migration, for the Red Admiral is unable to withstand the northern cold and does not hibernate north of the Alps.

The Peacock, the Comma, and the Small Tortoiseshell, though, are able to withstand it, and in the next few weeks will be seeking safe places to hide for the winter. With their wings closed, leaving only the camouflaged undersides showing, they are easily missed by predators. They are also easily missed by humans: when giving the garden shed its autumn turn-out it is worth remembering that some of these butterflies may well have staked their all on a crack or crevice in some dark corner.

There they remain, month after month, motionless and with their body functions almost at a standstill. A few warm days in March are enough to wake them, which is why Peacocks or Small Tortoiseshells are among the first butterflies to be seen in spring. Then there is no rotting fruit to attract them; they must break their fast with a purer nectar sipped from banks of heather or other early blooms.

It might be preferable to think of them at that spring, rather than this autumn, equinox, and, tiptoeing a retreat through the dew-soaked grass, leave the orchard and its inhabitants to their orgy of decay.

Collared Doves

The practice of keeping dovecotes is now largely a thing of the past, which is rather a shame, because a few white doves add greatly to the charm of a garden or courtyard. Better than domestic doves, though, are those born and bred to the wild. They make ideal "pets", because they are free to leave at any time, and there is none of the compulsion that to my mind mars the usual relationship of human with animal.

Unless you are very unlucky, you will have your own wild doves – Collared Doves – not too far away: slender, stone-coloured birds with a distinctive cooing song. They are fond of suburban back gardens, smallholdings, farmyards, and similar places, and where unmolested can become quite tame.

At a distance a Collared Dove looks almost uniformly greyish brown, but seen close to, especially in sunshine, it is a most elegant and attractive bird. The plumage is very delicately contoured and shaded, and a softly vinous flush on the breast harmonizes perfectly with the claret-coloured legs and feet. The eye, too, is in this register of red: when the sun catches it at a certain angle, it looks exactly like a ruby.

In its flight and habits the Collared Dove is a gentle, fastidious creature; the partial black collar, edged with white, is reminiscent of the velvet chokers once worn by dowager duchesses. The impression is completed by one of the bird's often-used calls, a loud _uhrrr, uhrrr!_ uttered as if in horror at the violation of its genteel sensibilities by the appearance of some unspeakably uncouth ruffian – perhaps even a flasher.

The Collared Dove has become so much a part of the local scene that it is hard to believe it bred in this district no earlier than 1966. The first arrivals were the subject of a series of excited notes on a brand-new card in my index box. The magic date was 25 May 1966, when a male was seen – studied at 30x through my telescope! – and heard singing on the roof of the house. By 4 June it had a mate and both birds remained in the area till the end of the year. _Definitely not a domesticated form. Very good views frequently obtained when seen drinking from gutter 15' from window. Wary and unapproachable._

Few bird-watchers now would bother to record "very good views" of the Collared Dove. But how and why has this bird become so common where previously it was unknown?

Nothing is ever static in the living world. Even the most apparently stable community of plants and animals is in perpetual flux, brought about by changes in climate or other environmental factors, or by changes in their own genetics and evolution. Change is in fact one of the chief characteristics of living things.

Normally this change is quite slow, taking the span of many human lifetimes to become obvious. Sometimes, though, it can be quite rapid, and occasionally, as in the case of the Collared Dove, it can be spectacular.

The most sudden changes come in the wake of some catastrophe, a natural disaster such as a forest fire, an earthquake, or volcano, which wipes out one community and gives a clean slate for the formation of another. Or the natural disaster may simply destroy one part of the community and alter its balance, allowing certain new forms to invade.

Man's influence on the environment can be seen as a series of natural disasters, both large and small, of this second type. Many species have lost out; some have gained from the opportunities inadvertently put in their way. When a species not only has a new set of opportunities put before it, but simultaneously undergoes a genetic or behavioural change enabling it to exploit new territory, then you can expect some fireworks.

The Collared Dove was originally a bird of the Indian sub-continent. Its principal food is grain, which pre-adapted it to benefit from man's increasing use of agriculture. As farming slowly became more successful the Collared Dove began to spread slowly north and west, reaching Asia Minor in the 16th century. By 1925 it was well established in the Balkans.

Then, suddenly, something happened. It may have been a slight genetic change enabling some individuals to breed more successfully; it may have been a behavioural change making the Collared Dove even more tolerant of man. Whatever did happen, the slow northward expansion of the previous few centuries became a full-scale invasion.

A record of its progress across Europe looks like one of those animated maps showing the advance of the Nazis: from Belgrade it reached Hungary in 1928 and Czechoslovakia in 1935. Austria fell in 1938, Poland in 1940. It reached Germany and Italy in 1944, Holland in 1947, Switzerland and Sweden in 1949. By 1950 it was breeding in France: the first (unofficial) British sighting was in 1952, the first breeding record in Norfolk in 1955. It first bred in the London area in 1962, and in our own district, as already mentioned, in 1966.

The earliest colonists were often to be found in the vicinity of chicken-runs, or at zoos or other places where spilled or otherwise free grain was to be picked up. This opportunism in feeding is one key to the Collared Dove's success. Another is its liking for conifers in which to nest – almost to order we busily planted our suburbs with Lawson's Cypress, ready for its arrival.

But the main key to its success is its fecundity. In mild weather the breeding season may begin as early as January and go on till October. It can tend the young of one brood while incubating the eggs of the next, and will tolerate levels of disturbance that would make most other birds desert.

The increase is still going on. In Britain it is extending its range into other habitats, especially farmland. Abroad it is still moving north and west, having reached Iceland, where this gentle invader may even be readying itself for the final, really big challenge, the one that even the Nazis couldn't get near: Canada, the USA, and all points south.

Fungi

Most English people instinctively fear and dislike fungi, and waste no opportunity to kick a toadstool to bits. A native of the continent, especially of eastern Europe, would find such behaviour quite mad, and would no doubt add it to the long list of eccentricities for which we are internationally renowned.

In all lands but this, wild fungi are gourmet fare. But here we eat only the insipid mushrooms that come in a safe plastic punnet, and leave the best to rot. Of all the hundreds of sorts of mushrooms and toadstools to be gathered from our fields and woods, only a few are dangerously poisonous. A large number will give you indigestion, even more are tough, tasteless, or otherwise inedible, but many of the rest are absolutely delicious.

Unfortunately it takes detailed knowledge to decide which are safe to eat. There is no general rule, no substitute for knowing each species – and its lookalikes – well. In England we have no tradition of such learning passed down from parent to child. What knowledge we have must usually come from books.

Overcoming this English phobia and finding wild mushrooms for the table often leads on to an interest in the fungi themselves. More than an interest: a fascination, an obsession. A walk in the woods becomes a treasure-hunt. The fungus-seeker's eyes are rarely raised from the ground, unless it is to scan the boughs overhead for bracket growths.

Fungi are now classified into their own kingdom, quite distinct from those of plants or animals. They are far stranger than any Martians. The range of forms and colours, of smells and textures and tastes, and of strategies for survival, shows a boundless cosmic imagination at work.

The majority of the world's 50,000 or more named fungi are microscopic. They have colonized almost every conceivable habitat, from pigeon droppings to the fuel tanks of Concorde. In a single teaspoonful of garden soil there may be as many as two million individual fungi existing either as spores or in active growth.

All but the single-celled fungi are built to the same basic plan, being made up of hollow filaments called hyphae. The hyphae combine in a mass, the mycelium, which constitutes the body of the fungus. In a field mushroom, for example, the mycelium lies mostly underground as a network of threads; the mushrooms themselves are the fruiting bodies of the fungus and of course only appear at certain times when conditions for spore dispersal are favourable.

A toadstool is a masterpiece of design, custom made for the job of spreading as many spores as possible. This it does in various ways, depending on the group to which it belongs. In the gill fungi, which includes many of the larger and more familiar mushrooms and toadstools, the gills are covered with tiny club-shaped projections called basidia. Each basidium carries four minute stalks, with a spore on the end of each one.

A mushroom with a ten-centimetre wide cap has a gill area of some 1,200 square centimetres. During an active life of five or six days, it will release something like sixteen billion spores – an average fall, day and night, of over 30,000 per _second_. Each of these spores is discharged in an ordered manner. Pressure is steadily increased at the point where the spore is attached to its stalk. The mechanism is not yet fully understood: but when the spore is discharged, it shoots away from the stalk to a distance of about 0.1 mm, or about 15 times its own length.

Then, falling down between the gills, it is carried away on air currents. Even the lightest movement is enough to bear it away. The other three spores on each basidium are shot off at intervals of a minute or so.

In order to achieve a free flow of spores, ripe basidia are evenly distributed among discharged ones and among those that are yet to fire. Both the stem and the cap respond to gravity, keeping the gills perpendicular to the ground and minimizing the chance of a spore sticking to an adjacent gill. The gills themselves are spaced and arranged for maximum efficiency. And, finally, most gill fungi take fruit in the autumn, when winds are strong, temperatures are right, and the weather is ideally damp.

Unlike green plants, fungi have no chlorophyll and so cannot make their own food. They must get it from other sources. Some fungi are symbionts, growing on or in other living organisms (even other fungi); some are saprotrophic, feeding on dead material. Symbionts may be of benefit to the host, or may weaken and eventually kill it, in which case the fungus may itself die or switch to saprotrophy. The distinctions are not always clear-cut.

The usual mode of feeding is via the hyphae, which ramify into a network invading the food source. Hyphae secrete chemicals that break down the food and allow it to be absorbed. The variety of things that fungi can use as food is staggering. Virtually any organic material – even the kerosene in Concorde's tanks – can be grist to their mill. Without them, much of the decay in the world would not happen and life for other forms would be difficult if not impossible.

Most of the larger fungi belong to an advanced group called the basidiomycetes (those fungi having basidia), and it is usually with this group that an interest in, even a love for, fungi begins.

The fungus fanatic could have no happier hunting-ground than Whippendell Wood, near Watford. The fungus flora there is so rich that during just a few visits I found well over a hundred different species, and I would by no means call myself an expert. The commonest sort overall is one named _Russula ochroleuca_ , with white stalk and gills and a yellowish cap, found growing singly or in small parties in the leaf litter under trees. Among the others are several of the most poisonous species known to man, and some of the most tasty.

Next time you take a walk in the woods – and what better month for that than October? – spare a minute to look at some fungi. Even if you're not sure of their names, you may find that the previously despised, overlooked and, perhaps, kicked to bits, is admirable after all and, in its own peculiar way, both impressive and beautiful.

Sleeping Rough

In Cassiobury Park at dusk I noticed a man of middle years, a little way ahead, making a slow and strangely aimless progress under the trees. Dressed in a dark overcoat and of outwardly normal appearance, it was at once apparent that he was anything but normal. His very walk betrayed him as one of society's misfits, mentally or socially deficient, unable to make sense of the crazy set of rules devised by the rest of us. He had the air of utter solitude, the desolation and loneliness that mark the tramp: and a moment later he stooped to examine a discarded cigarette packet.

There are others sleeping rough in the park and woods. Occasionally, in out-of-the-way places, their shelters may be found: comfortless lairs of brushwood and polythene, with a cache of empty old tins and packets near by.

Our own shelters are scarcely more permanent. We are separated from the wilderness only by the thickness of a pane of glass. Out there, as the winter begins to bite, conditions at night are frequently lethal for the soft, warm, high-tech machinery of our bodies.

The human animal evolved in the tropics, and is designed to work best in tropical temperatures. As man slowly migrated northwards he had to adopt new strategies for survival. The endless forests of temperate Europe teemed with game: the trade-off between cold and hunger was well worth the effort.

First he lost most of the pigment in his skin. It was no longer needed to protect the body from too much ultraviolet radiation, and even proved a handicap, for much of the body's vitamin D is produced by the action of sunlight on the skin.

To help with heat insulation, he became more hairy. Of more importance, he developed the practice of wearing clothes, using the pelts of prey animals. Clothes are as old as northern man himself: the arguments of nudists that it is more natural to go without them in these latitudes are utterly fallacious.

The most important asset of all was fire. The earliest true men, belonging to a species called _Homo erectus_ , used to keep a fire burning perpetually. Probably one member of the tribe was charged with tending it; when on the move, the fire was nurtured in the form of smouldering embers.

The capture and taming of fire represents one of the key feats in man's mastery of the environment. It must have happened independently many times and in many places over aeons of time. Fire occurs spontaneously in nature, often following a lightning strike. It has no substance, yet gives pain and destroys. Its forms and colours are those of a spirit. Early men must have viewed it with terror.

But they must also have noticed how a bush fire drives the game before it, and must have taken advantage of the opportunities spontaneous fires gave. Any animal that died in the fire and was part roasted would have been eaten too, and they would have noticed with pleasure how much better this flesh tasted and how much easier it was for them to eat.

Then, sooner or later, one individual, more daring than the others, made the leap of imagination that even then was the stamp of genius.

The invention of friction-fire is even more remarkable. As any Boy Scout will tell you, it's not just a question of rubbing two sticks together. Lighting a fire by friction is a difficult operation, as well as being hard work.

Another brilliant invention – the bow and arrow – gave rise to the bow-drill, in which the string of the bow is looped once round a stick. If the top of the stick is then held in place using a slightly hollow pebble, and the bow worked back and forth, the stick revolves at high speed. Result: smouldering punk-wood in a few moments, fire in a few moments more.

With ready fire and warm clothing, man moved ever northwards. The Inuit, whose unique way of life is now becoming a thing of the past, reached the ultimate in ingenuity with their igloos, houses made of snow itself.

The ingenuity of our ancestors in southern England led to winter pit-dwellings that must have been extremely cosy. Excavations at Stone Age campsites show an impressive degree of co-operation and skill in the construction of these pits. Roofed with branches and ferns and lined with skins, such a house would be occupied by a whole family group. Each occupant acted as a radiator, and after a very short time the interior temperature would be well up into the comfort zone.

In building these dwellings, as in a vast range of other techniques, the people who used to roam this landscape were experts at survival. Nearly all their skills depended on mutual co-operation and division of labour within the tribe. Solitude for a Stone Age man meant certain death, and probably, as in some primitive tribes still clinging on today, expulsion was the ultimate punishment.

The unfortunates sleeping rough in modern Britain have none of ancient man's knowledge, nor can they draw on the inexhaustible supply of food the forest provided. Whippendell Wood would barely support even one family. The ecosystem has effectively been wrecked: the tramp must depend on the grocer's shop along with the rest of us.

The grocer's shop relies on an agriculture which would be virtually impossible without chemicals. If for some reason the supply of chemicals ceased, the whole structure of our society would collapse.

The old and unfit would simply die. For the rest, the black-and-white laws of survival beyond the window-pane, now faced only by the tramp, would become the new reality.

On an early-autumn night, that is a sobering thought indeed.

Stocker's Lake

The flooded gravel pits between Watford and Denham, following the course of the River Colne, have now mostly reached the stage where they resemble natural lakes rather than gaping holes in the ground. It does not take long for the vegetation to soften the outlines; and with the vegetation of course come the birds.

Our local lakes are now among the best places in Hertfordshire to see birds of all kinds, especially wildfowl. One of the pits, indeed – perhaps the most attractive of them all – is a nature reserve looked after by the Hertfordshire and Middlesex Trust for Nature Conservation.

This is Stocker's Lake, near Mill End. It lies between Bury Lake (part of the Aquadrome) to the north-east, and Springwell Lake to the south-west. Along the northern and western sides runs the River Colne; along the southern runs a picturesque stretch of the Grand Union Canal, opposite the farm where location shots for the TV serial _Black Beauty_ were made. The lake itself figured in many of the programmes: it is ideally photogenic.

Stocker's Lake was one of the first of the gravel pits to be excavated, and has been in a natural state for most of this century. As a result, the trees are well established, and the lake is almost as interesting for land birds as it is for waterfowl. The southern shore is especially well wooded, being lined with mature willows, alders, and birches.

When in spring or summer the wind blows from a northerly point and you yourself are on the north shore, the whole mass of willows seems to turn silvery white as each of the leaves turns its underside to the light. The contours of the foliage are almost completely natural, untouched by pruning. Sometimes a great bough or even a whole tree comes down and blocks the towpath.

The water area, extending to about 68 acres, is broken up by a variety of islands large and small, and by a peninsula on the southern side. The largest stretch of open water is in the eastern half, and provides good feeding for grebes and diving ducks such as tufted duck and goldeneye. This part of the lake is usually the last to ice over; the ducks and coots themselves keep a patch open for as long as possible by swimming ceaselessly round and round.

In the middle of the stretch, grounded on a reef, lies an old gravel barge. Until recently a few of its ribs could still be seen protruding above the surface, a line of posts much perched upon by gulls. Another sunken barge lies near the meadow behind the canal lock-keeper's cottage.

One or two of the islands in this eastern end are quite extensive and, rarely trodden, make a true sanctuary for wild creatures. Others again are overgrown with sallows; others yet, alternately covered and exposed by the changing water level, remain almost bare.

Along part of the northern shore, a group of islands and strands forms a maze that in winter is a favourite daytime roost of cormorants and herons. The birches and willows are frequented by flocks of tits, goldfinches, siskins, and redpolls: it is impossible to see all the birds there. Some idea of their numbers is suddenly and unexpectedly gained when a sparrowhawk, flying fast and low, makes a furtive dash among the trees.

The sheltered water among the maze of islands is a haven for mallard, teal, pochard, and shoveler, with smaller numbers of gadwall, and occasionally wigeon too. Stocker's Lake is a good place for certain rarer ducks, and has in the past yielded red-crested pochard, goosander, smew, and pintail. There are geese here too: Canada and grey lag, with occasional feral birds of other species like barnacle or lesser white-fronted.

Not far away from the maze of islands, also on the northern shore, is a small section where the bank, loose and earthy, has crumbled into a series of miniature cliffs, lined for much of their length with a narrow reed-bed. Now, at the end of November, the reeds are sere and tawny-yellow, and make a dry rustle in the breeze. Seen from the top of these cliffs, the surface of the lake on a sunny morning dazzles the eye.

With every yard of the perimeter walked, the aspect of the lake changes. The course of the Colne curves with the shore; by an island in the river there is an old cast iron bollard, now almost hidden in the scrub on the farther bank. A similar bollard stands on the towpath: they mark the boundary for collecting taxes on coal formerly brought into London. The coal collector's residence, a Georgian house with its upper storey overlooking the lake, can still be seen beside the towpath just below the lock.

Further along from the first bollard, by another island in the river, there is a rickety stile. Beyond it lies a rough, hawthorn-dotted pasture where horses graze.

Here the lake shelves gently. It is fringed with rushes, watermint and fleabane. As small boys we used to swim from this spot. The water was warm, but, a yard or two below the surface, even in June and July, lay cold pockets that denoted the presence of deep hollows in the lakebed. One day at the end of May, while swimming, a party of black terns, accompanied by the more usual, white, common terns or "sea-swallows", miraculously appeared and gave a graceful display of effortless aerobatics before slowly moving on.

Even if it were allowed today (actually it was frowned on then), a swim in Stocker's Lake is not to be recommended, if only because the water has underground continuity with overspill from the canal, and who knows what pollutants come down that particular highway? But the other charms of the lake are intact and, safeguarded now by the Trust, should remain so for the future.

Leaf-fall

All but one of our native British trees are deciduous, shedding in a few weeks of autumn their canopy of leaves. The leaves contain green chlorophyll, held in bodies known as chloroplasts. It is in the chloroplasts that the main business of the tree is carried out – photosynthesis, the manufacture of sugars and other organic compounds, using carbon dioxide, water and trace elements, the whole reaction being powered by sunlight.

As much attention to detail is lavished on an individual leaf as on the whole tree. Each one is a miracle, a factory filled with chloroplasts. To work properly the chloroplasts must be kept wet, so the leaf is enveloped in a waterproof envelope and air is only allowed to enter through special pores that can be opened or closed at will.

Then of course the products of the chloroplasts must be conveyed to the rest of the tree, and waste matter taken away, so the leaf is provided with a complete network of veins.

When you think how many leaves are put out each spring by, for example, an oak tree, it seems an insane act of wastefulness to throw them away again at the end of the summer. Yet, such is the cost of maintaining a broad leaf in working order during unfavourable weather that it actually pays the tree to adopt the deciduous habit if its leaves are of that type.

In equatorial forests most broad-leafed trees keep a perpetual canopy of foliage, shedding leaves in small numbers all the year round. The same is done here in the temperate zone by a few broad-leafed trees, like the evergreen oaks, and the world over by pines, spruces, and the other "official" evergreens. In fact all trees everywhere regularly shed leaves that have reached the end of their working lives. Looked at like this, the autumn leaf-fall does not seem quite so profligate.

If a branch is killed, the leaves merely wither. They do not fall: the autumnal leaf-shedding is a carefully controlled operation, involving the least possible loss to the plant. Preparations for it have been going on since the summer.

Whenever a plant deliberately sheds an organ – be it a leaf, a petal, a whole flower, a fruit – a special separation layer is formed where the split is to take place. The layer is made of cells with an inherently weak jelly-like middle. Meanwhile, below this the tree forms a sealing layer that will keep out bacteria and fungal spores when the separation finally comes.

As the growing season reaches its end, the tree reclaims whatever it can from the leaf. Valuable trace elements are resorbed. The chloroplasts are gradually allowed to die, losing their green colour. The delicate conducting vessels that, all summer, have carried sugars out of the leaf, are one by one shut down and their point of entry into the system sealed off. All that remains are the tougher, woodier, water-conducting vessels.

Having lost its chlorophyll, the leaf is given colour by its residual pigments. Chief among these are xanthophylls and carotenes, which have an important job to play in the chemistry of the leaf. The autumn yellow of, say, the birch or sycamore is solely due to these.

There are other pigments, too. The golden yellow of beech leaves is produced by a brownish pigment, probably tannin, which is present in addition to the xanthophylls and carotenes. The more prominent reds and purplish-browns of the autumn woods come from a group of compounds called anthocyanins – which also give the red, purple or blue colour to many flowers.

The best autumn pageant comes only when the weather promotes the development of anthocyanins, when there are extended periods of bright, clear, dry weather with cool but not freezing night temperatures. This weather is the norm in autumn in New England, where the display of maples, oaks, and cherries attracts large numbers of admiring visitors every year.

The display in our own woods and gardens is not bad, either. Our native trees have a marvellous range of yellows, reds, and browns. The beech, of which different individuals turn at different times, offers perhaps the most beautiful show of colour, but such trees as the field maple, willow, rowan, and wild cherry can sometimes put in a really glorious performance. Then there are all the introduced trees, many of which have some fine autumn tints.

By the time the leaves are at this stage the whole metabolism of the tree has undergone a profound change. The hormonal balance – for plants, like animals, control their tissues with hormones – has tipped in favour of the dormins, a group of compounds prominent, as their name suggests, in the dormancy of seeds and buds. The growth-promoters of late winter and spring have been largely replaced by growth inhibitors. There is a build-up of these compounds in the area of the separation layer.

A leaf on the point of falling is held in place only by its separation layer, its outer skin, and the woody water-conducting vessels in the middle of the leaf-stalk. Wind and gravity between them work to free the leaf's hold; the end often comes after a hard frost, which freezes the jelly-like middle of the separation layer, making it expand and forcing the cells apart.

Each breeze then thins the foliage, revealing more and more of the winter skein of twigs. The tree, the sugar factory, has shut down until spring: but next year's leaves are already formed, crammed into buds.

When they reach the ground the old leaves are seized upon by an army of invertebrates and broken down into rich soil ready for future generations of leaves, and for future generations of trees and for all the other plants and animals that depend on them. So in the end nothing, really, is wasted after all.

Mandrake

On this night our thoughts turn to the darker side, to magic, witchcraft, and wonderworking. The cycle of seasons has entered its decay: we are heading downwards into winter, and no mortal hand can hold us back. In pagan Europe since time began there has been a celebration at this time of year, a feast, a defiant bonfire. Like Beltane, the old midsummer fertility festival in honour of the Sun God, this celebration has its origins in the furthest mists of antiquity.

The name has been changed to Hallowe'en now, the eve of All Hallows Day or All Saints' Day (1 November), but that was merely an attempt by the church, in 834, to convert a heathen festival into a Christian one. So deeply rooted was this old festival that 2 November was also made over, in 993, to All Souls' Day, a day to pray for all those in purgatory.

The distinction between science and sorcery can be a slender one indeed. Although feared and hated for his powers, the ancient shaman or the medieval warlock was also accorded the greatest deference. Only later, as knowledge replaced superstition, could people afford to persecute witches.

Chief among the arsenal of the witch were the weapons provided by the plant kingdom, and chief among these was the most arcane plant of all – the mandrake. Even today, its name alone is enough to conjure a feeling of slight unease.

There are actually six different species, natives of southern Europe and the Mediterranean lands. The mandrake is a relative of the deadly nightshade, belonging to a group that contains some of the most poisonous plants in the world.

In life the mandrake has little or no stem, and oval leaves that are erect at first but soon come to lie flat on the ground. The flowers, an unhealthy looking greenish-yellow or purple, are bell-shaped and grow on stalks about three inches high.

The mandrake's fame comes from its root, which can grow three or four feet underground. When forked, this root can resemble a gnarled and knotty little man. A guiding principle of the old herbalists was that plants often, by their appearance, give some clue as to their uses. Because the root looks like a whole man, the mandrake was especially highly esteemed.

In fact it is one of the oldest recorded plants of magic. In the Book of Genesis it features in the story of Rachel and Leah, two sisters who were rivals for the affections of Jacob. Rachel, it is plain, wanted mandrakes because she was unable to bear Jacob any children. Jacob lived 6,000 years ago: even then the mandrake was valued as an aphrodisiac and for its supposed property of ending sterility.

It is also the oldest known narcotic. The Greeks and Romans called it mandragoras and used it as an anaesthetic during surgery, for treating wounds, gout, erysipelas, and as a sleeping draught.

Shakespeare knew of this last use. The villain Iago mutters against Othello: "Not poppy, nor mandragora, Nor all the drowsy syrups of the world, Shall ever medicine thee to that sweet sleep Which thou owed'st yesterday". And Shakespeare knew the darker mandrake too: in Juliet's "horrible conceit of death and night" she imagines "... shrieks like mandrakes' torn out of the earth, That living mortals, hearing them, run mad—"

For the figure of the mandrake root was believed to be more than a mere symbol. Thomas Newton, in his _Herball to the Bible_ , says, "It is supposed to be a creature having life, engendered under the earth, of the seed of some dead person put to death for murder." The screams of this demon, when uprooted, would infallibly bring madness and death to all who heard them.

This may have simply been propaganda put about by the herbalists, as mandrake root was very valuable. Propaganda or no, in due course they came to believe it themselves, and had to devise a cautious way of harvesting the crop. "... the uprooting must be performed at midnight, within three magic circles described by a sword, and with strict attention to the direction of the wind." First the plant was loosened by digging all round it with a spade. Then the brave herbalist, having stopped up his ears with wax, fixed a stout cord to the plant and tied the other end to a dog. Retreating smartly, he tossed a piece of meat a little beyond the outer circle so that the dog, lunging for the meat, pulled the mandrake from the soil. Not very sporting, but ingenious.

In the middle ages, mandrake root was carved into miniature figures and sold at high prices as good luck charms. In France the figures represented a wealth-bringing elf called Mandegloire. Popular as they were, these charms were dangerous to own and could bring an accusation of witchcraft. One of the charges brought against Joan of Arc was that she carried such a figure in her bosom.

Both Lucrezia and Cesare Borgia used mandrake as a poison. In low dosage the drug produces a quickened heartbeat, raised temperature, and dizziness – probably the symptoms that led people to think of it as an aphrodisiac. Heavier or repeated doses cause delirium, coma, and finally death. Medicinally, the root was prepared by allowing it to rot (for 60 days, according to one recipe) before being eaten or made into gruel.

Today we can afford to smile at the old superstitions, sitting snugly, and smugly, under electric light on this Hallowe'en. But how many of us enter the doctor's surgery in a state of blind faith, willing to believe everything we are told? Are we not just as credulous as those medieval peasants with their Mandegloire talismans?

And what if the lights suddenly went out, and from Gibbet Lane, or Gallows Hill, there came, at midnight, a shriek, a blood-curdling scream? What then?

Moles

The onset of the frosts often brings signs of renewed mole activity, especially on pastureland. One morning it seems that freshly turned molehills are everywhere. There appears to be no pattern to them; an army of excavators has been at work; but if carefully studied it emerges that the heaps usually belong to a single burrow system inhabited by a single mole.

The "moudiewart" is not much of a socializer. Except when male and female briefly meet, of necessity, in the early spring, any encounter between moles usually leads to a fight, often vicious, and sometimes to the death. They are subterranean hermits, irascible and solitary. Their world, just a few inches underfoot, is quite bizarre; and they are wonderfully adapted to it.

Few people have seen a dead mole, never mind a live one, but of those who have, most are surprised by its smallness. A really big buck, so called, is no more than five and three-quarters inches long and tips the scale at something under five ounces.

Yet, for its size, the mole is one of the world's strongest animals. In just twenty minutes it can evacuate as much as ten pounds of soil, or fifty times its own body-weight. A twelve-stone miner would have to shift four tons in the same period to work at a corresponding rate.

To fuel this tremendous effort, moles have a voracious intake of food, consuming about half their own weight every day. The main item of diet is the earthworm, but other soil invertebrates like slugs and leatherjackets are taken too.

The burrow system serves to trap whatever stumbles into it. The mole makes regular patrols, snapping up food as he finds it. When caught, a worm is seized with the jaws and pulled through the huge forelimbs in a special way, which cleans it of much external dirt and at the same time helps to void the contents of its gut. This done, the worm is either devoured in a matter of moments; or, in some circumstances, bitten in the head, to immobilize it, and stored to be savoured later. A mole's pantry may contain many worms: the record is 470, weighing almost two pounds!

Periods of frenetic activity lasting about four and a half hours alternate with periods of about three and a half hours in the nest, sleeping it off. The cycle goes on regardless of day or night.

Some foreign species of mole are completely blind, with the eyes not only reduced but actually covered with skin. Our mole has not quite reached this stage. If you blow gently, you can part the plush pile of the fur to reveal tiny bead-like eyes. They can just distinguish light from dark, but probably not much else.

Nor is hearing of great importance. The external ear has gone altogether – it would only get in the way during burrowing – and the internal ear is not specially well developed. Taste and smell are also rather rudimentary.

Of much more interest are the mole's other senses. It is keenly sensitive to touch, and can detect minute vibrations in the soil. Groups of tactile hairs are found on the chin and muzzle and the tip of the tail. The snout, pink and hairless, is covered with thousands of papillae called Eimer's organs. These are specially sensitive, particularly when the slightly erectile tip of the snout is gorged with blood.

The function of these Eimer's organs is not really known. They certainly register subtle changes in touch, and perhaps in smells too. They may also be affected by changes in temperature and infra-red radiation, enabling the mole to "see" in the dark.

Even more remarkably, it has been suggested that Eimer's organs might also work as "teletactile receptors", sensitive to minute changes in air pressure. By this means the mole could tell at a distance when it was approaching an obstacle or even a prey animal. The vibrissae may also help the mole to detect compression waves in the air, and certainly warn it of approaching obstacles.

If a mole's senses are well adapted to the underground life, his anatomy is better adapted still. A mole is a digging machine, a furry bulldozer purpose-built for the job. The whole animal is tube-shaped. Its skeleton is heavily reinforced for attachment of the digging muscles and to allow free rotation of the shoulders, which are powerful and relatively massive. The forepaws are developed into efficient shovels, fitted with strong claws.

Put down on almost any surface but concrete, paving, or asphalt, a mole will immediately dive into the ground. A breast-stroke action is used, frenziedly repeated until the tip of the tail vanishes. Once underground the mole progresses with alternate motions of either forepaw, the other being used, together with the hind feet, as a brace.

In soft earth the spoil may simply be compacted into the sides of the tunnel, but in firmer ground it is ejected at intervals through specially made vertical shafts, and forms the molehills that are the bane of gardeners and greenkeepers. Sometimes, in very soft soil, moles make tunnels so close to the surface that the ridges may be clearly seen.

If he is lucky, a young mole will inherit a tunnel system ready-made, but often as not he has to start, so to say, from scratch. The construction of a complete tunnel system is a colossal task. Without seeking planning permission, tendering for contract, putting up a signboard, or bothering with a starting ceremony, the mole just gets on with it.

The system always incorporates a nest, a spherical chamber lined with hay and leaves. Here the mole sleeps, or if she is pregnant, gives birth to the tiny pink molelets. In places liable to flooding, the nest may be sited in an abnormally large molehill. These big hills, or fortresses, can be a foot high and a yard across.

Once the basic system is dug, it is refined and enlarged with other tunnels, crossing and branching and on a variety of levels. From then on most of the mole's work consists of keeping it clear of obstructions.

When the weather turns cold, the mole moves into deeper tunnels that might not have been used since the spring. Repairs and alterations produce spoil; and it is this spoil that appears above the ground at the start of frosty weather – as sure a sign as any of the coming winter, and an outward clue that matters proceed in the industrious, hermitic life of the mole.

Hunting Sparrowhawk

Seen from the open peak of the hill, a female sparrowhawk rises above the massed trees of the common. She is slowly spiralling, riding the warm air coming off the sunlit pastures of Home Farm. The sky, balmy blue, carries streaks of cirrus that enable the leisure of her ascent to be gauged: two hundred feet, three, three hundred and fifty, four; and still she climbs.

This is one of the ways a sparrowhawk hunts. It's a precise equation, the balance between altitude and acuity. The higher she goes, the more ground she can scan, but the harder it is to discern her prey. At five hundred feet, her eyes are still doing their job perfectly. Her vision is not quite as capable as that of the watcher a mile away, but he does have a pair of ten-power binoculars to mark her progress upwards.

Six hundred feet now. The hunter's attitude subtly changes. She has at last found something possible below; and commits to the plunge. Her wings are brought in close, held clenched. She is making a brutal, racking fall, accelerating down from the sun at an angle of eighty-five degrees.

Fifty crazy feet above the pasture, maybe even lower, travelling at sixty or seventy miles an hour, she lurches out of her stoop. Her flailing wings are glimpsed; her talons stretch for the prey, a desperately speeding lark or thrush.

She has missed. The swerving pursuit continues across the field, becomes half-hearted.

Above the hedgerow the hawk gives up. Without seeming to slow, she enters the foliage of one of the trees at the edge of the common, and there abruptly vanishes.

Linnets

Much of rural Hampshire is like this: a landscape devastated by agriculture, the forest climax destroyed, never to return while men are on the scene. Many species of bird have lost out, but a few, adapted to life in edges and clearings, have gained.

There are not many birds about this morning. Along the muddy, winding lane leading from the Manor, rain-sodden telephone poles make the only trees. Rising at intervals from a hedgebank of almost leafless hazel, their trunks throw out a few stunted laterals of galvanized steel. A cable, sagging between the top of each pole and its neighbours to south and north, is all that remains of the woodland canopy.

The storm that began the day has almost passed over, sweeping on north-eastwards, making the sky there dark. In the opposite direction the approaching cloud is thinning, fuming, promising a break: and suddenly, just when the day could not possibly become more miserable, fleet sunlight bathes the winter wheat on your left. The hedgebanks are lit up, the glistening poles, the pasture on the other side, the stolidly munching bullocks. Thus illuminated, these things, seen against the wall of leaden sky beyond, might lift a less preoccupied spirit.

Then, miraculously, a flock of linnets rises from the pasture. There are eight or ten of them. They flash and tinkle in the sun, white, brown, russet, grey, their calls too rapid and intimate for the laggard human ear to follow. For a moment they perch along the telephone cable, making a pattern of notes, a linnet-tune that dislodges a few sparkling drops into the hedge.

You have been seen: with more twitters they flee, over the arable, and, half-circling, with mysterious concurrence of will, find a patch of ground to their taste. Like dislodged rain they too drop down, and immediately begin to feed.

As you walk on, the sun goes in and the rain resumes, but your day is no longer of the same.

Brent Geese

At lunchtime on a grey Friday, the harbour is quiet. The tide is halfway out. A few brent geese are visible to the south, feeding at the edge of Fowley Island.

Chichester, Langstone and Portsmouth Harbours are home to thousands of these birds each winter. For geese, they are insolently tame, yet their sheer numbers generate a special excitement.

A great flock, heard at a distance, gives off a curious, howling vibration. At first this seems like the noise of massed, unsilenced, two-stroke engines: go-karts, perhaps. But it also has something of hornets buzzing round the nest, and then one realizes it is being made by brents. Each bird's repeated _ungh_ contributes to the chorus.

They don't like passing raptors. A peregrine generates a storm of geese. Even a kestrel can flush quite a large flock, five or six hundred strong. The process of flushing involves craning anxiety, hesitation, a cascading decision to go. At the instant of takeoff all members of the flock seem aligned in the same direction. That huge biomass launches, gets airborne, circles over the rough grazing, the wire fence. They fly out over the sea-wall in a broad arc, sweeping back inland again and directly overhead, forming a moving canopy some fifty or sixty feet up. As they come over, the width of the flock continues expanding, causing an extraordinary perspective effect.

But today, at Emsworth, there are fewer than a hundred. A small group passes by, low over the grey water. The tide has fallen past a critical point, exposing some favourite mud. For no good reason you suddenly suspect that this little flight is a regular thing, part of a comfortable routine. The geese know all the best spots.

They cross the border from West Sussex into Hampshire and, pitching near the harbour wall, contentedly begin to feed.

Unchanged Selborne

"... Golden-crowned wren, Regulus cristatus: Its note as minute as its person; frequents the tops of high oaks and firs: the smallest British bird."

(From a catalogue of birds in Gilbert White's second letter to Daines Barrington.)

On a gloomy afternoon, among the dark branches of yews by the Zigzag, flitting movement disturbs the eye; the hearing registers the needle-thin calls of a goldcrest. The tiny bird has reached the end of a bough. For an instant it raises its head, revealing the bright orange crown. It is a male. Behind him, still foraging spiders among the yew-needles, is a female.

Goldcrests are so small that a man must seem incomprehensibly huge. They are very tame. The bird flies off, perhaps at sight of the biped's form. More likely, he has decided to search elsewhere. His metabolism is like a shrew's: he must gorge or die.

Especially where large or extensive, most conifers have their breeding goldcrests. After an average winter, some 20,000 pairs breed in Hampshire. The yews on the Common stand mainly in isolation among deciduous trees, but even they are home to an occasional nest.

Now is the time to savour the weak, repetitive, almost tuneless song. Once learned, its final flourish, like early spring sunshine, never fails to gladden the heart.

Words from My Nature Journal

Saturday, 4 May 1963

We saw six swifts heading NE (hawking for insects?) A jackdaw floated down to a little clump in the lake and tackled a shellfish.

Wednesday, 14 August 1963

Today we went on the "Nemo" to the Bishop Rock Lighthouse, and saw the mail being hauled back and forth on a rope. On the way here I saw quite a few grey seals, which kept bobbing up to be photographed and then disappearing again. Also I could see a rock that was covered in guillemots and razorbills, but we did not get that close. There were shags and cormorants, and gulls on the rocks near by.

The boatman told me that we could not land on Annet because you need a permit, and anyway there was nothing to see there any longer, the puffins having all gone two weeks earlier.

On the way back to St Agnes I saw two gannets.

Sunday, 29 September 1963

A vanguard of lapwings passed over, heading roughly SW, with a gull at either end.

Thursday, 10 October 1963

The owl came over, uttering many querulous and squawking noises, and finally settled in the silver birch. I could see that it was the size of a jackdaw, but much blunter bodied and broader winged.

Sunday, 27 October 1963

I visited the old mill, but not much there. A wren flew out from under the lock; I suppose it had been searching for beetles in the rotting beams.

Sunday, 3 November 1963

There were five partridges sitting on barbed-wire fences in a field opposite the woods, and they flew rapidly off on whirring wings at my approach.

Further up the same field, another covey of seven were scratching in the stubble. I stood watching them for a while through my telescope.

Saturday, 14 December 1963

To the woods this morning – it was bitterly cold and snowing delicately. I sat on a bench in the meadow where, on June 8th, I saw a tree pipit.

Sunday, 12 January 1964

Whilst the hare disappeared over the field, I saw a large bird from the corner of my eye. It was a heron, and it flew into the wood.

Eager to discover its business in the wood, I plunged through the brambles and dead bracken until I saw five or six of these great birds winging off through the tree canopy.

Underneath the trees they were resting in were several patches of droppings, and I found several ghost-grey contour feathers, which from their large size indicated herons'.

Saturday, 18 January 1964

It was very cold and a thick frost covered the ground, and all but one of the many molehills in Birch Glade was frozen, indicative of the very cold night.

Sunday, 8 March 1964

There was a dabchick diving in a bend of the river this morning. I sat under a weeping willow and watched the opposite bank. A brown rat went from the woodpile down to the stream, but I didn't see him after that.

Saturday, 21 March 1964

It was at first light when I awoke. As I walked down the main park, the distant parish bell sounded six as the early morning mist began to recede.

Sunday, 5 April 1964

Everywhere the birds were in pairs – yaffles, blue tits, rooks, carrion crows, jays, blackbirds, song thrushes, woodpigeons, dunnocks, great tits and chaffinches.

I left the sun over my shoulder as I descended into the coolness of the wood, brambles and bluebells (not yet in flower) covering the ground.

Monday, 6 April 1964

The dusty sun cast long shadows from the avenue trees.

Tuesday, 7 April 1964

It was very cold when I left home – about 25°F, but as the morning grew on it became progressively hotter.

We descended to the marsh, soaking our boots as we forded the river. Lesser celandine was in flower here.

We flushed a drake mallard from a pool, and I thought there might be a nest, but I found nothing.

Saturday, 11 April 1964

Along the path down to Leeswood Cottage two chiffchaffs were singing. In the scrub along this path an exquisite male brimstone butterfly flew by.

In the glade I saw a butterfly which could only have been a white-letter hairstreak. If so, it must have been a very early emerger, as this species is usually on the wing only in July.

Monday, 13 April 1964

Over the Gade a house martin, the first of the year, was hawking. Near Bridge 168, in a marshy ditch, was a pair of blackcaps. I only caught a fleeting glimpse of the female, just long enough to see her rusty scalp, but the male was most obliging, and I watched him for a full minute before he was off and away.

Tuesday, 14 April 1964

Just off the River Chess we saw a cuckoo, which, however, was not calling. It was a large bird, somewhat larger than a mistle thrush, and with a blue-grey back and spots at the tip of each tail-quill.

Sunday, 17 May 1964

The terns, especially the Sandwiches, kept going off to fish in a nearby bay, and as they returned the other terns set up a welcome of "keeoorik keeoorik", and the returning bird would reply using the same call.

I noted the Sandwich terns' slight crests, which stood up against the wind.

Saturday, 23 May 1964

The sky was cloudless; the sea blue. The white terns soared and wheeled against the blue, now and then plunging for a fish into the shallow water.

Sunday, 7 June 1964

Near the grass field I flushed a hen pheasant off her six stripey chicks, who remained absolutely still, "frozen", only their eyes betraying their presence.

Saturday, 11 July 1964

The tide was in and due to recent rains much of the marsh was flooded. Several lapwings rose up from the flooded grass, calling querulously.

The wild horses on the marsh grazed peacefully.

Monday, 17 August 1964

It was raining very hard when I set out along the sea wall.

Thursday, 3 September 1964

Two herons hoisted themselves aloft, barking as they winged over the lake.

Saturday, 24 October 1964

After some rest and a meal and dry boots, we returned to the marsh and saw a grey plover, and a party of bird-watchers including the "maestro of bird photography", Eric Hosking.

Saturday, 31 October 1964

The leaves on the trees are every shade of brown, green and gold imaginable, but each breeze thins them out, and great drifts may be seen in the streets.

Saturday, 7 November 1964 – morning

Half a mile away, over the marshes, a shelduck planed down.

After an explosion all the birds in the estuary, including 250 curlew, 8 mallard, and one wigeon, 300 varied small waders and 50 redshank, flew up and swirled around for some time before resettling.

Saturday, 7 November 1964 – afternoon

Next, I got stuck in a bank of oozing, sucking, slurping, oily MUD.

The mud sucked off my gumboots and I had to dig my stockinged feet into the mud to free myself, then dig the boots out with a piece of wood.

Saturday, 21 November 1964

From here I went up to the woods. There was little here, but a few owl-pellets were collected from Localities A and B, an analysis of which appears in the Survey.

Sunday, 29 November 1964

It began to rain softly and coldly. We walked up Drayton Ford and along to Maple Lodge. We put up the jack snipe, but it pitched again after flying twenty yards.

Friday, 25 December 1964

It had been snowing a little during the night, and it was a fine, clean, but cold, morning.

Practically the first bird I saw was an unmistakable drake pintail, which was flying quickly over the lake NE–SW. It had fairly long wings, a light belly, dark head with a light stripe up the side. Its back was grey and the body tapered out behind into a needle-thin tail.

Sunday, 24 January 1965

Each minute the number of gulls coming in grew, until at dusk 2,000-3,000 were riding on the northern part of the water. Thousands more must have been on the KG6.

Then, against the sunset, about half our birds went up, say 1,500, and went over to the KG6. Truly a tremendous sight; and a fitting end to a rewarding day.

Saturday, 6 February 1965

Today Tim Cox and I built another hide on the second cress-beds.

Later in the day, at about 1400, I went home for lunch and Tim went off to the new beds to look for Ian Johnson's pipits.

I returned to find a jubilant Cox; he had seen a water pipit on the new beds.

Saturday, 20 February 1965

I had a talk with the water bailiff, and he was complaining of the louts out and about.

Sunday, 21 February 1965

After completing the count, I crossed the waterfalls, went over the mill, and into the marsh, where I found winter heliotrope.

At the old beds I flushed three or four snipe from the area round Hide B: they have grown accustomed to it already.

Tuesday, 23 March 1965

At the old disused cress-beds I found a partially completed blackbirds' nest in the old hut, on a shelf in one corner. There is a nest in this place every year, but it is invariably robbed.

There were a couple of redpolls over the ditch – and – amongst the saplings, the first two chiffchaffs this spring, one of which I watched for a time before it flew off with its mate. They were not singing.

Friday, 9 April 1965

Just as I passed the clearing, a hare bounded down towards the shed.

From the woods I went down the field (grass this year), down to the canal, along the towpath, and home.

Sunday, 18 April 1965

Near the coastguard's cottage were 20-30 waders, mostly turnstones, but with two ringed plovers and one unidentified bird, probably a dunlin.

Saturday, 24 April 1965

Round by the marsh there was a sedge warbler, and swimming between the reed-beds and the peninsula was a strange duck, which another bird-watcher told us was a ruddy duck, and had been about the reservoir for some weeks (bred here: British Birds 60:1, p. 29).

Thursday, 13 May 1965

As I was walking down to the old cress-beds, at 0550, a male kestrel flew over the huts towards the tennis courts.

Saturday, 22 May 1965

This morning Tim Cox and I went up to the wood to hear the dawn chorus. Here is the order in which the birds woke up:

Tawny owl  
Robin  
Blackbird  
Starling  
Song thrush  
Rook  
Blue tit  
Mistle thrush  
Woodpigeon  
Wren  
Cuckoo  
Blackcap  
Willow warbler  
Great tit

Saturday, 19 June 1965

Among the gravel strands on the little pit, almost invisible amongst the clusters of persicaria, were about 20 migration-weary lapwings. Some were birds of the year, and all were extremely sluggish.

Saturday, 26 June 1965

A green sandpiper fluted up from the side of the big pit, flipped over the causeway with an effortless, fluid movement, and dropped among the water-plants. I walked back, and flushed it over to the island.

Wednesday, 25 August 1965

Then, as we walked along the causeway, Tim saw two waders on the "foreshore", not twenty feet from us. We slid down to the concrete lip and began to take notes. We saw four ruffs and – so we thought – five dunlin.

These "dunlin" turned out to be five little stints (notes and sketches p. 517).

They were fantastically tame: in fact once I was within a range of eight feet of one. Part of the time they were so close that every detail could be seen perfectly without glasses!

Saturday, 28 August 1965

Skokholm is a small island lying off Milford Haven, Pembrokeshire, at a distance of about two miles. "Discovered" in 1936 by R. M. Lockley, it has since been taken over by the West Wales Naturalists' Trust.

The only buildings on the island are the observatory and the lighthouse. The observatory consists of a house, ringing room, kitchen-cum-hall, and sheds for accommodation.

Vegetation on the island is limited to bracken and close heather, with turf in many places, kept short by one of the largest rabbit densities in Europe. The geology is mostly red sandstone.

Being a bird observatory, the chief occupation of the observatory is trapping and ringing migrants, but an important sideline is ringing Manx shearwaters. This is undertaken during the summer, when the birds are breeding.

The technique involved is to go forth at night, when the adults come to feed the young. After a certain time the chicks are no longer fed and they are forced by hunger to leave the burrow and fly away.

Catching the birds is both painful and most enjoyable sport. When grabbed, the chick squeals and screams and bites the first object that comes into view. If possible it flaps its wings and struggles with the legs.

A party of perhaps five people, four "catchers" and a "ringer", leaves the house after records have been written up. The ringer carries four or five hundred rings and an incandescent lamp, and the catchers take torches to locate the birds.

During one night of eight or nine hours' ringing a total of 1,250 was ringed by all parties.

Sunday, 29 August 1965

After supper we lazed around until it was time for the customary cocoa and writing up of records.

Around 2210 the two parties set out for shearwatering again and a total of 600 was ringed. We finished at about 0240 on the 30th.

Sunday, 26 September 1965

At Wilstone Reservoir we saw a bat flying c. 15 feet up, near a thorn bush next to the old canal chute. BPP said he thought it might be a pipistrelle or a Daubenton's or similar bat, but we agreed that under the unusual circumstances flight behaviour could not be used as identification.

Saturday, 26 February 1966

We finished lunch and climbed the embankment. On the top there was a gale blowing, throwing plumes of spray over the concrete bank. In a corner where the jetty meets the coping, cross-waves had a spectacular effect, making spumes with every wave. We got round to the corner after quite a soaking, and one fall on a piece of muddy ground; rounding the corner, we walked into the teeth of the wind and battled our way to the windbreak corner.

Saturday, 5 March 1966

Also, at the end of the pipe I found some fox droppings. When dissecting the older of the two I found that it contained a .22 calibre waisted airgun pellet, one of the more expensive brands, probably a Webley or a Milbro. Undoubtedly one of the louts that frequent the lake must have shot a gull or some other bird, which the fox subsequently ate, the pellet passing through its digestive system unaffected by the gastric juices!

Monday, 11 April 1966

In the Marrams was a juvenile kittiwake, too exhausted to resist when I waded out to investigate. It was in transition plumage from juvenile to adult, and had us extremely puzzled for some minutes before it was apparent that it was in fact a "tarrock". We took some photographs of the wing-plumage, and also of the head. We placed it on the shingle and it soon recovered enough to flap away. When we returned later in the day it was nowhere to be seen.

Further along was a dead gannet, oiled on the secondaries; the bill was serrated in such a fashion as to allow easy entry of food, and to hinder its exit. This must be a valuable evolutionary feature of the gannet, as when diving under the sea it must be difficult to keep a slimy fish in grip without some device like this. Near by was the dried remnant of a guillemot, also oiled.

Thursday, 14 April 1966

In low willows by the causeway were 2 chiffchaffs, looking excessively miserable, and some yards further along, also in willows, was a pair of sand-martins, resting. On the water were several grebes, mallard and coot. As we walked round the reservoir, sand-martins stayed very close by the coping, coming within 4 feet of us. This was true at Wilstone; and every time they flew into the wind towards us they suddenly relaxed their flight muscles and allowed the wind to whisk them back 15-20 yards.

Sunday, 10 July 1966

HCD spotted a pinkish, amorphous object lying in the mud along the west shore. After some time it became apparent that the object was in fact a kestrel in a bad state. It was a young bird, with very pale scapulars and an uncoloured cere. Evidently it had stooped at a pipit or sparrow, or more likely one of the pied wagtails, misjudged the dive and landed in the mud. This was recorded recently in British Birds, where a kestrel and a meadow pipit were found dead together in a sewage farm. The kestrel was still breathing, but it would have been fatal to try and make one's way across the mud.

Monday, 25 July 1966

The gulls are moulting their summer dress off at the moment and several house sparrows in the area were collecting the white contour feathers as they floated down on the wind, probably because the sparrows wanted them for nesting materials.

Friday, 9 September 1966 – Malta

In the grounds of the Kennedy Memorial I watched a female black-eared wheatear flitting restlessly among the low saplings and once it brought its wings forward, almost in a curtsy, when attacking a small lizard.

Monday, 31 October 1966

A weasel ran out in front of my motorcycle and although I swerved I ran the animal over. It was a male (shown by dissection by M. Burger).

Saturday, 31 December 1966

This morning we repeated Thursday's sea-watch. The most interesting bird seen was a red-throated diver. It was badly oiled and after several minutes was drowned by a heavy wave.

Friday, 6 January 1967

Today we were luckier with the crossbills, seeing about 60, and one party of eight exceptionally well. There were some males, females, and juveniles, working some pine-cones with their peculiar beaks.

Other birds seen in the pines included two woodcock, a green woodpecker, a redwing and goldcrests, a great spotted woodpecker and long-tailed tits.

Early in the afternoon we saw a female hen harrier briefly over some heathy ground near the pines.

Monday, 17 July 1967

Inside the hide I discovered a wood mouse peering intently at the notes I was writing. It was between the outer and inner layers of canvas and looking through a hole in the inner layer.

Saturday, 19 August 1967

On the leeward side of the Head, in conifers and rhododendrons, were at least 1,000 starlings, perhaps 2,000. These birds were just waking up (it was first light).

Monday, 23 October 1967

About 200 yards offshore was a badly oiled puffin, a juvenile. Three black terns were heading west along the shore. About 500 yards out in the surf was an adult red-throated diver in winter plumage.

Saturday, 9 December 1967

About 100 moorhens were roosting in unfrozen water on the Pond (most of it was frozen). One moorhen was on the causeway in weak condition, unable to fly. It floundered onto the ice when I approached.

Thursday, 18 April 1968

The tide was well out, and in a shallow pool some 35 sanderling and 10-15 dunlin were bathing.

Thursday, 9 August 1973

About 150 yards offshore, at a point opposite the midway cottage, was a loose flock of eiders, composed of 7 ducks and 5 drakes in varying eclipse plumage. The eiders were feeding actively, diving and coming up with fish; a duck was seen to shake one of the fish violently before swallowing it in a single gulp. The flock seemed unconcerned by my presence. With them was a first-year great crested grebe, also feeding actively.

Other ducks seen were about 50 mallard over the marshes, and 23 teal: a party of 4 flying west over the saltmarshes, and two parties of 4 and 15 respectively flying west out to sea. 20+ shelduck, including a juvenile bird, were about.

Many Sandwich terns, over 140, were plunging into the surf along the beach; a high proportion of them were juvenile birds. In plunging, some remained completely submerged for a perceptible amount of time before reappearing – with or without a sand-eel. A single little tern was seen, and c. 50 common and/or arctic terns: positive identification was made of both species.

There was a dead adult kittiwake on the beach not far from the coastguard lookout; one of its legs had been removed. Near the iron "bedstead" (which has now collapsed) was a dead common seal, probably a 1973-born animal, as it was only about three feet long. Part of the flesh about the face was gone, revealing a set of remarkably canine teeth. I turned the corpse over with my toe: underneath were two crawling patches of maggots. Reclamation workers.

Out to sea the main movement was again to the west. Not far from the beach were regular parties (2, 5, 4, 4, 4) of oystercatchers, a single sanderling, and 4 dunlins, while further out a heron, the teal, and a party of 4 unidentified gulls/skuas/large waders also passed westwards. No scoters were seen. At 0850 a third-autumn gannet flew east, and later a similar bird (perhaps the same one) flew west. It was not seen diving.

Thursday, 18 October 1973

I saw a fox in the south-west corner, loping through the willowherbs. The sun was in its eyes, and it only made off when it caught my scent.

Monday, 5 November 1973

Over 30 snow buntings were about, mainly feeding by puddles near the pill-box next to the coastguard station; no Lapland buntings or shore larks were to be seen.

Wednesday, 10 September 1975

For a few moments I watched a kingfisher perching on a low branch over the water. It plunged and seemed to come up with a minute fish, then perched again on a different branch, this time a dead twig a few inches above the surface. A second later it flew behind the island and was lost to view.

Tuesday, 16 September 1975

On the Colne by the cattle's drinking-place was a pair of mute swans with four large young: this family has been present all summer, on the river between Black Jack's and Moorhall Meadow. Originally there were six cygnets; then on 20 July there were only five; and on 26 August, four. "Sportsmen" are the likeliest explanation.

Thursday, 9 October 1975

The arrival of winter visitors was in great evidence today, with parties of redwings and fieldfares on the north pasture, and unusually high numbers of duck. Altogether 16 snipe were seen, on the east and north shores, and by the Colne; and flushed from the bank in square 16 (eastern shore) was the first jack snipe I have seen in seven years. It rose in silence, performed a few half-hearted evasions, and pitched again in the north-east corner, on the margin of the lake, near the copse of hawthorns.

Tuesday, 14 October 1975

Meadow pipits too were in evidence, and over the North Pasture one of a party of three flying west parted from its companions and gave chase to a swallow, which was inadvertently passing the three pipits, moving south. The chase was quite intense, the swallow desperately trying to avoid its pursuer; unfortunately the episode was concluded behind a row of trees, out of my sight. I have often observed pied wagtails chasing other, seemingly harmless, birds – most inappropriately, collared doves; perhaps the Motacillidae have some pugnacious streak in their character. It is hard to understand the purpose of this sort of behaviour. Surely it bears a similarity to mobbing, but doves and swallows can present small threat to survival.

On the South Pasture by Moorhall GP were about 10 mistle thrushes, together with about 15 song thrushes: probably migrants. I saw no "winter thrushes", except for a single redwing near Black Jack's. Also there was a green woodpecker, a bird quite frequently seen in that area. Presumably the rough pasture provides plenty of ants; and the quiet copse of oak and willow between the restaurant outlet and Troy Mill GP must be to its liking.

Thursday, 4 December 1975

Many thousands of starlings were roosting in the larch plantation at the Ovaltine Farm.

Tuesday, 16 March 1976

A dull morning today, with a mist over the hills. Scattered in several small parties about the lake were roughly 35 very vociferous Canada geese, perhaps already paired and preparing for breeding. A single drake shoveler was among the gravel islands, and a pair of shovelers near the south side; two pairs of goldeneye were fishing.

Friday, 10 December 1976

Following a night of hard frost, the lake was mainly frozen, a clear patch remaining in the south-east corner, and it was here that many of the wildfowl, with a single great crested grebe, were to be found. A flock of about 130 teal was on the ice by the gravel strands, almost opposite the end of the peninsula: the largest flock I have ever seen in the Colne Valley.

Saturday, 1 January 1977

Large numbers of redwings and fieldfares, on all parts of Croxley Moor, but mainly in thorn bushes by the canal between Dickinson's Mill and the Met. railway bridge, reached a total of about 400, 200 of each species. Recent hard weather (on 27 December it snowed and remained very cold for the following days) may have brought them. Certainly the berries are very abundant this winter.

Friday, 4 March 1977

After the heavy rains of recent weeks the level on the pit was the greatest for many years. The water in the south-east, sand-coloured from the churnings of the completely submerged beach, was breaking in waves almost at the top of the bank, driven before a fresh wind. Across the lake few of the gravel-islands remained exposed; and, perhaps because of the choppy surface, wildfowl were few. Two drake goldeneye and three morillons were fishing, among the tufted ducks and the grebes.

On the south pasture a flight of about thirty lapwings straggled up against the wind and went down on the causeway by the Colne on the NW side, among twenty more lapwings and a flock of (mostly white-hooded) black-headed gulls. The south pasture by the river has flooded: the sluice from the big pit to the smaller was inches under water, and the excess has brimmed from the small pit to the pasture. Near by six greylag geese, and seven swans, were grazing. About 50 Canada geese, including the old pale-headed bird (now looking quite grizzled), swam on Tilehouse. Nine more swans fed on the bank.

A kestrel flew off from its perch on a post of the fence beside the small pit and the south pasture.

Some twenty-five cormorants were on the alder islands. Some of the trees have been killed and bleached completely white by their droppings.

On the north pasture numbers of yellowhammers, skylarks, and tree sparrows were busy feeding among the cattle.

Thursday, 24 March 1977

Thirty or so cormorants rested on their customary island, from time to time sallying forth to swim, back down, beak up, in search of fish. For one of these gluttons a free meal was provided by a heron, which with what might be described as embarrassment seemed to have caught a fish (at a distance thought to be a chub) far too large even for its capacious jaws. The heron, unable to get a purchase on the fish, put it down in the shallows by the edge of the cormorants' island. The fish struggled and appeared partially paralysed, incapable of escape. Several times the heron stabbed at its catch, and even seemed to peck off morsels and swallow them. For a while, one foot on the fish, it stared down, perhaps wondering what to do. Presently, after a few more pecks, the heron stalked on yellow legs a number of paces round the edge of the island, and seemed to stand in meditation, its head askew.

The cormorants, which had previously showed a keen interest in the matter but seemed reluctant to challenge the heron directly, now took action. The charge of one of their number, an immature bird, down into the water, brought several others after it; but the first bird's enterprise paid: it seized the fish and gulped it down at once.

Moments later the heron returned and really seemed to express great puzzlement. It looked stonily at the shallows, here and there on the island, at the shallows again, before relinquishing all thought of the fish. By way of consolation it casually reached down and lifted a minnow or other small fish from the shallows, and in seeming absent-minded contemplation of the ripples opened its beak and took the minnow down.

Friday, 6 May 1977

By Little Westwood Farm two partridges – seen too briefly for identification – whirred away and behind a hedge. On the fields of Model Farm, and by the margin of Berrybushes Wood, several pheasants were feeding, including a melanistic cock. Two or three of the hens appeared very pale, sand-coloured. More pheasants were heard corking in the wood itself.

The lapwings, five pairs in all, were much in evidence on the broad hillside and among the new green fields by the path. As I crossed the field to the south-east corner of Berrybushes Wood the lapwings circled overhead, calling: probably there were eggs or chicks near by.

Chiffchaffs, willow warblers, and a blackcap were singing at the edge of the wood. Turning up the north side, I heard a cuckoo towards Jeffery's Farm; perhaps another bird called later from the southern part of the wood; and later still the first bird had moved much nearer, to the plantation above path A59.

At the south side of the valley on my way back I stopped to study the wood through binoculars. Wood pigeons and starlings flew over the stands of spruce. A bird of prey – a Falco with possibly a brown back – came across the treetops, moving south-west. A crow flew with it for part of the way as it gained altitude. It climbed still higher, wings sickle-shaped, and when directly overhead inclined its head to direct both eyes at the ground. Then, sliding west, it crossed the field boundary at five or six hundred feet. I followed its course over Buck's Hill, where for a moment it may have hovered (confirming it as a kestrel); resuming its way, it passed over Commonwood, over Hillmeads Farm and, following the valley, dived to Belsize and was lost to view.

Friday, 29 July 1977

A passage of sand martins was in progress this morning. About 250 birds were feeding, mainly low over the lake, and with fluttering wings perched for a few instants on the old dried stems of water-plants and on the tops of the willowherb on small gravel islands by the stands of water dock and purple loosestrife.

Sunday, 1 January 1978

Starling: at 1530 c. 2,000 seen in several flights from the east/south-east, descending on elms at King's Langley Farm. In the next 25 minutes more flocks, each of 100-2,000, arrived from most directions, though mainly E. Huge flocks performing evolutions over King's Langley (Langley Lodge Farm). Birds still arriving at 1557. Total in excess of 20,000. By 1600 the elms were abandoned; bulk of birds seemed to move north or north-west, towards Chipperfield. More were arriving at 1605.

Thursday, 12 October 1978

From Bottom Lane I walked up through Buck's Hill Wood and across to Little Westwood Farm. A male kestrel flew across the hayfield and perched in an elm. The air was slightly blue with haze in the extraordinary warmth, funnelled by southerly winds from Africa. At the swing-gate I heard red-legged partridges: a pair and a single bird were standing on two of the many rolls of hay left by the machines across the slope of the field. The partridges flew off at my approach. Later, by a field-edge at Juniper Hill, I saw a covey of about 20.

At the bottom of the hill, where paths A45 and A46 cross, a female sparrowhawk, burly and bar-breasted, suddenly flew up and dived over the trees of, appropriately enough, Hawk Spring. She followed the line of trees south-eastwards, flushing out in her progress a spray of sparrows, finches, blackbirds, rooks and wood pigeons.

Tuesday, 8 December 1981

Snow had been falling during the night and for most of the morning, leaving a three-inch layer on the ground and clustered on every twig and branch, for the wind had been light. After lunch the sun came out.

A cormorant was perched on the favourite willow in the middle of Hampermill Lake, and another appeared later. Wildfowl on Hampermill and Tolpits was rather sparse, especially on Hampermill, although on Tolpits were at least 40 shoveler – outnumbering the mallard – and a flock of 85 pochard. On Hampermill near the shore was a pair of pochards: with the sun behind me, the drake's eye looked molten red, like the old name, "poker".

One of the boughs of the old willows had collapsed under the slight burden of snow, so recently as to cover a set of bootprints. These trees are quite old and notices warn that they are dangerous. Along the river path I came upon two dabchicks in the current. They dived and came up again by the flags. Under the trees the light was quite extraordinary; the sky, blue overhead, was pink and hazy to the north-east and light green elsewhere, reflecting in the water.

Sixty lapwings flew down the line of the valley, WSW, a sign of the cold weather. They were followed later by five more.

At Tolpits, along the north shore, were no fewer than ten herons. They were perching among the osiers and willowherb and, one by one or in pairs, flew up at my approach.

Despite the snow the water was almost completely open. As I left, however, the ground was already beginning to freeze.

Thursday, 28 January 1982

This afternoon I walked the length of the disused cress-beds by the New Field. One or two siskins were calling by the upper waterfall; beside the old brick culvert, low down in an alder, was a male siskin that was unusually tame, allowing superb views – I approached nearer than the focusing of my binoculars would allow – before it flew away. Siskins appear to be on the increase. In the recent hard weather they, together with other small birds able to feed aloft, suffered less badly than the rest. Some goldfinches (a "charm" of five, seen on my last visit to Bury Lake) even made a virtue of the freeze: where an alder overhung the ice it had shed some seed ready to be picked up, saving them the trouble of their usual acrobatics.

Friday, 12 February 1982

The herons already appear well advanced in their renovation of last year's nests: half a dozen or so platforms showed in the branches of the island trees. The islands also attract roosting stock doves. In the late afternoon in winter they arrive from several directions and wheel about before settling. Today there were more than fifty, mostly arriving at about half-past three. I left before dusk, when more could be expected.

Sunday, 18 April 1982

Eight drake and one duck pochard were swimming about near the large alder islands. As they swam they all followed more or less the same direction, only to change direction, keeping up a continuous chorus of grating calls. One or two of the drakes seemed especially agitated, extending and also apparently thickening their necks, bills pointing slightly upwards and seemingly thrust forward. It was as though all the drakes were paying court to the duck. The ceremony lasted for some minutes; when the birds went behind the islands I thought I could still hear their calls, though these may possibly have come from a nest of herons. When they emerged again I was able to observe that the drakes sometimes made a little dash forwards during their progress; and, before extending the neck, the body, neck and head were briefly laid along the water, recalling the aggressive/territorial posture in coots or great crested grebes.

Thursday, 19 September 1985

The rooks at Welling Grove were "swirling" – all gliding in much the same plane just above treetop height – and calling excitedly, frequently with that peculiar screaming cry they have. They soon flew off, over the pylon wires, to the fields to the west.

Sunday, 16 February 1986

A single redpoll came down briefly at the cress-beds, which, still covered with snow-dusted ice, today presented a perfect view of a jack snipe.

This bird was feeding continuously, making slight springing movements with its legs. It remained obligingly in one spot, a few yards from the corrugated-iron fence, on an open stretch of mud and low tangle of cress, allowing the details of the plumage to be observed. The crown was all dark; the bird seemed generally darker and more definitely marked, and had a much shorter bill, than the common snipe that equally obligingly pitched near by. The jack snipe was a noticeably squatter bird, with an abruptly pointed tail.

I have not seen one hereabouts for over ten years; the very cold spell (first snow fell on 5 February and it has yet to thaw completely) may have brought it.

The cold may also have encouraged the water rails to show themselves. I believe there are at least two resident in winter at these beds by the railway viaduct. One came out into the open, giving prolonged and detailed views, just a few yards from the jack snipe. Head on, the water rail gives a close-eyed impression: its eyes are like buttons, inclined together by planes of the skull dictated by the shape and length of the bill, which is quite stout at the base and well suited to prodding about in the mud. The grey-blue of the head and neck tones wonderfully with the warm brown of the body, which in turn is suited by the striped flanks and buff under-tail coverts. A strange, secretive and chicken-like bird. Its companion raced across the beds, using the low cover of the concrete wall.

Sunday, 13 March 1988

A sparrowhawk flew north, accompanied by a carrion crow that soon "peeled off". The hawk gained height, rising to several hundred feet, and then, wings held close, made a shallow dive to Copper Mill Down, flushing starlings and crows as it went. I last saw it, barely visible at that range, flying low past the hawthorns on the hillside.

Sunday, 3 April 1988

At the corner of Rousebarn Lane, where it rises towards Gade Bank, I saw an adult Chinese muntjac with a fairly small fawn. They climbed the bank into the woods; I climbed the bank likewise and saw two or three adults and three or four fawns, getting excellent views of one adult: these are small, peculiar, hunch-backed deer, as russet as a fox. I saw the facial mask of an adult that peered at me with relative unconcern; and saw clearly the long, drooping tail which, lined with pure white, is conspicuous when raised.

On 8 July 1983, on a very hot afternoon, I was studying fungi in Whippendell Wood (in E4) when I saw a small, antlerless deer, about which I made the following brief notes: "plain rump, humped appearance, tail edged with greyish white," [obviously the tail was not raised on that occasion] "barking call, rufous coloration, rounded ears. Calls uttered singly, at c. 8-second intervals. (Muntiacus sp.)"

The animal seen then was extremely shy. In Southern's 1964 Handbook of British Mammals its presence is described as "often difficult to detect, and may go unsuspected". This text also says that the fawns are born in late summer, but have been recorded in November and December. The fawns I saw today must have been no more than a couple of months old, probably less.

Friday, 7 October 1988

The strong wind was keeping most of the smaller passerines under cover; the water in the centre of the lake was being whipped into fairly sizable waves, and few ducks or coots were there. The wind accounts for the low species-count today.

House martins, moving generally south along the river, were feeding in the lee of the trees that stand on the rise between the Colne and the main road.

Lack of birds was compensated for by the magnificent formations of cloud, thunderously grey and dazzling white, by the glitter on Moorhall GP, and by the appearance of a hemi-rainbow rising from Mount Pleasant. The trees are shedding their leaves very quickly: autumn is upon us.

Saturday, 13 November 1988

A female black redstart was perching on a pile of kerbstones near the gates to King George VI Reservoir (opposite the footpath to Staines Reservoir). A black redstart, probably the same one, has often been reported in this area, and apparently shows a fondness for the ornate brick valve-towers of Staines Reservoir itself.

A sparrowhawk was again seen above the trees of the northern embankment; and we obtained wonderful views of two female kestrels that spent much of the morning hunting over the causeway itself. Seen in the telescope, the head of one hovering bird remained motionless with respect to the field of view: its eyes were focused on the slope of the sunlit embankment on the southern side of the causeway.

Sunday, 8 January 1989

In a long, drawn-out flock, floating on the sea not far from St Peter's Chapel, were at least 450 great crested grebes, together with a smaller number of mallard; the tide, fully in, was exceptionally high (there was a new moon yesterday), and the line of coastal defence barges was almost completely submerged: hence the grebes were not too far out, and a little later, also not too far out, I saw three or four red-throated divers, with at least two more seen in flight later.

Tuesday, 20 June 1989

A tractor was mowing the large pasture above the cress-beds; the hay was so dry that small and not-so-small tangles of it, thrown up by the blades, were being caught on the breeze and wafted on a thermal, climbing hundreds of feet and drifting this way and that, slowly descending when their own weight became too much for the supporting air.

Thursday, 13 August 1992

Three Arctic skuas were over the sands at the end of the Point, near to the herd of about 90 seals hauled out in two parties. The skuas were harrying Sandwich terns, and each other; one or two individuals occasionally alighted on the sandflats for a short while before resuming feeding.

A passage of sand martins seemed to be in progress as I returned to the old coastguard lookout, with about 40 birds passing westwards behind the shingle and over the seablite bushes.

Wednesday, 16 November 1994

I had wonderful views of a short-eared owl hunting low over the tawny, wind-bent grass of the field beside the Great Deep. It turned this way and that, lightly stopping, going on, scrutinizing the vegetation and the ground; and finally dropped out of sight. A few minutes later it was up again, weaving among scattered clumps of brambles, moving into the open, retracing its path.

As dusk arrived, so did thousands of starlings, which seemed to be roosting in the large reed-bed near Thorney Road.

Tuesday, 22 November 1994

In Charlotte's Vale five herons were standing about and on the remains of a fallen lime; very hunched and miserable they looked too. Thirteen moorhens were grazing in the field near the Dower House. A grey wagtail briefly perched on the lip of the overflow channel beside the towpath.

Saturday, 31 December 1994

Many Brent geese, wigeon and shelduck were in the northern end of Bosham Harbour, and about twenty redshanks were sitting on the railings by the embankment, waiting for the tide to fall. Most of these flew off, low over the water, and settled on the shores of Eastfield Farm.

Out in Bosham Channel was a party of fifteen mergansers, with a couple of dabchicks near by. At Cobnor a little egret fed briefly in the ditch below the sea wall, but was soon away, disturbed by walkers. Where Bosham Channel flows into Bosham Deeps a single Slavonian grebe was fishing – only the fourth bird of this species I have seen, and the first for over twenty years.

By the time I reached Cobnor Point the tide was noticeably lower and flights of waders were arriving and eagerly feeding on the emerging mud. Many dunlin were present, with plenty of ringed plover and curlew, grey plover and oystercatchers. A party of three pintail flew north-west, becoming hidden by the bend in the shore.

The long islet off the point was full of roosting curlews, shelducks, and gulls. I watched them from the foreshore, where gnarled oaks have their roots exposed by salt-wash and further up a thicket of tamarisk lines the beach.

At least two more egrets were on the western side of the Chidham peninsula; in Thorney Channel were two parties of goldeneye, while in Nutbourne Channel were over sixty mergansers and a couple of great crested grebes. A large lapwing flock, originally seen on Thorney Island, took wing and drifted over the estuary, revealing a single golden plover among them. Turnstones were feeding among the weed, turning bits over to look underneath.

The first shower came then, quite intense; a double rainbow appeared on the right. A covey of seven grey partridges, in a field near Hovel Barn, were the only gamebirds I saw all day. The second shower, which struck me near Chidham Point, brought a single rainbow, but a complete one, spanning the whole north-eastern landscape.

Large areas of mud were now exposed. A peculiar sort of howling emanating from the direction of Emsworth at first seemed to be the distant noise of massed, unsilenced exhaust pipes: go-karts, perhaps, or stock cars. It also had something of hornets buzzing round the nest: and then I realized it was being made by Brent geese, a huge number of which were arriving to feed on the Nutbourne shore. Each bird's repeated "ungh", or "ungh-aungh", helped to make up the curious, vibrating chorus.

More Brent geese were feeding on the winter wheat when I cut inland, back towards Chidham village. A man with a golden retriever was making a poor job of scaring them away. They are insolently tame, and appear to know very well they are trespassing. They take no notice of the plentiful Calor-powered cannons and scarecrows with dayglo heads.

Wednesday, 4 January 1995

The waders were more or less tightly packed together in monospecific groups, the redshanks at the back, downwind, the dunlin, with heads under wings, massed like cobblestones at the front.

Friday, 13 January 1995

A female scaup was on the Little Deep, together with, but keeping aloof from, a few tufted ducks. It was thus possible to compare the two species. The scaup was noticeably heavier and broader, with a characteristically smoothly rounded skull. Elements of grey were seen in the mottled feathers of the flank. When it dived, it did so with a noticeable leap, more energetic than that of the tufted duck.

No short-eared owls were to be seen, but my scrutiny of their likely terrain – the furzy ground beside the Great Deep – was rewarded by a distant glimpse of a male stonechat.

Monday, 30 January 1995

After January's heavy rain, part of Sarratt Bottom was flooded. On the flood were three black-headed gulls, a pied wagtail, a grey, and a green sandpiper: the first I have ever seen at Sarratt. I did not wish to disturb the sandpiper, but it flushed anyway, towered on flicking wings, and headed towards the south-east: perhaps to some other part of the Bottom.

Wednesday, 8 February 1995

A short-eared owl was hunting over the furzy terrain by the Great Deep. It perched for a while on one of the fence-posts by the channel, resting and preening.

Wednesday, 5 April 1995

The old oak tree in the outlet by Black Jack's was being felled today. It has been dead for several years; nonetheless, it's sad to see it go.

Wednesday, 10 May 1995

A general disturbance of the lapwings, wildfowl, waders and starlings by the Great Deep heralded the appearance of a female marsh harrier. I first found it soaring at a height of about 500 feet, when I took it for a buzzard; I then lost it, and saw it a minute or two later over the reeds and scrub, when the yellow head was clearly visible. It tried to quarter the area, but was continually pestered by two carrion crows that probably had a nest near by. From time to time it climbed to avoid them, before returning to ground level to continue its attempt at hunting. At one stage it pitched among the reeds and remained out of sight for half an hour or so. As far as I know it had again settled on the ground when I left.

Thursday, 18 May 1995

A pair of marsh tits was nesting high up in a rotten birch next to Wood Pond, repeatedly bringing caterpillars to the nest-hole.

Not far away to the north-west, in a stand of beech by the path, I heard a wood warbler singing, but could not see it: the canopy is already too dense.

Friday, 19 May 1995

As I arrived I saw a white "heron" in flight, coming towards me, which then dropped out of view. Later this turned out to be a spoonbill, which spent the afternoon on the inner section of the lagoon, often feeding with side-to-side sweeps of its bill.

On the lagoon below the sea-wall were plenty of resting and feeding little terns, oystercatchers, shelducks, lapwings, and a party of 12 dozing black-tailed godwits. Many redshanks were about, some singing and displaying: the grass marsh is an important breeding site, as it is for lapwings, which were vigorously chasing intruding crows.

Friday, 28 July 1995

Many redshanks were on the Lake, among them an albino, almost pure white except for a few buff patches on the wings. Here too were over a hundred black-tailed godwits, a snipe, a curlew sandpiper in breeding dress, two little stints, a greenshank, upwards of four common sandpipers (two more were on the Deeps), and (seen later) two spotted redshanks.

Wader numbers in Langstone Harbour are increasing, with some 600 oystercatchers and hundreds of curlew on the islands, with greenshank (at least four identified) and whimbrel (number uncertain). A little egret was with them.

Wednesday, 30 August 1995

At the southern end of the main pond I glimpsed a hobby as it dodged over a tussocky bank. The light was superb, and in that moment I clearly saw the head markings and one rufous thigh-patch. Although I searched for the bird, I could not find it, and continued on my clockwise circuit of the ponds.

From the army road on the western side, I was watching a stonechat among the rushes when I saw a hobby on the far side of the pond, flying below the pines there. A moment later another hobby appeared. The range was about 400 yards. Both perched in the pine trees, and after a while I continued, taking the track to Cranmer Pond (nothing doing there).

I had left my bike on the north-eastern side of Woolmer Pond, and as I approached it saw the two hobbies again, flying low over the mud, snatching dragonflies. A few minutes later two more appeared, making a total of four. Two at least were full-plumaged adults, and two may have been well grown immatures: this may have been a family party.

The grace and expertise of their hunting made marvellous viewing, the birds now criss-crossing over the drying surface of the pond, next winnowing along the edge of the pines, or swooping up to some bough for a few moments to consume the prey. Most of the dragonflies were eaten on the wing, the head bent and the clenched talon brought forward. It seemed that only part of the insect was eaten, the rest being discarded.

The hunting birds seemed almost to be at play, so effortless did they make it look. I stood in the shadows of the pines, in a slight depression, and was ignored. When I came a little farther out, one of the birds suddenly saw me and seemed alarmed, gaining height, eyeing me all the time and, at a height of some hundreds of feet, moved out over the middle of the expanse of mud and rushes. There it apparently decided I was negligible, and thereupon closed up its wings and stooped almost vertically a hundred feet – as the quickest way of killing altitude – before coming out of the dive and resuming its work.

The hobbies were still hunting over this part of the pond when I left the area.

Friday, 22 September 1995

I heard at least one bearded tit calling from the reed-beds of the Little Deep; while I was standing there, a buzzard flew north, being mobbed by starlings, and a water rail called.

The buzzard had put up a swirl of wildfowl and waders, including fifteen little egrets, seven or eight of which briefly and picturesquely perched (or posed) on a low tree.

Many greenshanks were present, and a large flock of starlings was feeding on rough ground near the seawall. These birds later perched on the telephone or power lines going out towards the army base, so many together that I thought the lines might not bear the weight.

Tuesday, 13 February 1996

On the rough pasture near the guardpost, a flock of about 600 Brent geese kept quite tightly together: when a female kestrel flew harmlessly by, most of them went up, disturbing the lapwings, which then mobbed the kestrel until it passed on. Later, all these geese took off again and flew out over the sea-wall in a broad arc, sweeping back inland again and directly over my head, forming a moving canopy of Brents some fifty or sixty feet up. As they went over, the width of the flock was still expanding, causing an extraordinary perspective effect. "Skein" is the perfect romantic word for geese on the wing.

A rock pipit was busy among the weed and flotsam of the tideline just below the sea-wall. Its plumage, smoky olive with elegant dark streaking, contrasting with a somewhat paler throat, is more than mere camouflage: for a cold, raw afternoon at Thorney, it is aesthetically correct. Though its feathers were slightly puffed out, the solitary bird looked content, self-contained, as it walked and darted here and there. Presumably when darkness falls it finds somewhere with a bit of shelter: some blocks of broken concrete, the lee of a creek in the saltmarshes. I wonder if it must sleep lightly, fearful of a land-borne rat or fox, or whether it is wiser than that, and can judge a secure place to roost.

Thursday, 22 February 1996

One of the first birds I saw was a juvenile eider, with a whitish breast, a little way offshore; a Slavonian grebe was near by. In all there were at least four Slavonian grebes about today, with a few great crested and a dabchick in the harbour near Black Point. A rather smudged and dusky red-throated diver was swimming strongly north-west, towards Emsworth, off the beach at Sandy Point.

In the lee of the dunes by the sailing club I sat and watched the knot, grey and ringed plover, dunlin, redshanks, curlew, turnstones and bar-tailed godwits that had descended on the newly exposed mud and sand. In the telescope I was able to see the knots' sewing-machine feeding action; they stuck together, flighting quite readily, though they seemed unafraid of me.

Wednesday, 13 March 1996

Two cormorants arrived from the WSW at about 1115 and settled in the northern end, by the reeds, but looked guarded and uncomfortable, and ten or fifteen minutes later took off again. They circled clockwise, twice, perhaps reconfirming their bearings (cf. 31.7.66), then gained altitude and flew purposefully off to the NE. Perhaps they had stopped at Frensham en route from the coast to the reservoirs and gravel pits of the London area.

Friday, 14 January 2000

By dusk, thousands of dunlin were gathering with other waders on the spits south of the beds, performing their usual aerial display before roosting. In all I should say that at least 3,000 dunlin were present this afternoon, with grey plover, ringed plover, curlew, turnstones, redshank and knot.

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