-Ready?
[music]
-Well, I'm Vladimir Pravosudov. 
I'm a professor of biology 
at the University of Nevada, Reno.
-My name is Ben Sonnenberg. 
I'm one of Vladimir's graduate
 students in UNR's Ecology Evolution
and Conservation Biology Program.
-Overall, we're interested in how animals 
are able to find their way around. 
We all need to navigate places.
For example, Ben, where's
 the necessary nest box close to here?
-28-2 is just right over the hill.
-Yes, it would be. 
Then there's a 29 and we can
 remember where exactly they are. 
If you're turning around the corner
then there's a weather station. 
The bottom line is we used to find some
 landmarks as we tried to find it. 
Well, here we study mountain chickadee.
-[whistles].
-The birds that can cache tens
 of thousands of individual seeds items 
and then remember all their location
which is by far more
 impressive than a human can do. 
The goal of our work is to find out 
how important their memory
is because they use special memory
 to find all of these individual locations
and they need to find this food. 
Unlike us, if I don't find my nest box
I'll probably still have a nice lunch.
If a chickadee doesn't find 
its caches, it most likely going to die. 
Well, we're going to show 
you here our field site
and how we study mountain chickadees 
and how they find their caches.
[music]
-We're looking for caches.
-There's one. [?]
[music]
-Yes, that's good. 
I'm at one of our many feeder locations
around our field site 
at Station Research Forest. 
These are high-tech RFIDs or Radio
 Frequency Identification Equipped Feeders. 
Each one of these feeders
 is equipped with a battery
and a small computer
 board that opens 
and closes a mechanism that allows access
to the seeds inside one of these feeders.
This specific system 
and its array of eight feeders 
that all hang together in the woods
allows us to do memory 
and learning experiments on wild mountain
 chickadees in the Sierra, Nevada.
The first step to our research 
is to band as many birds
as we can throughout our field site. 
We set up nets around 
our feeders which remain open.
-[?]
-Yes. I'm going that way.
When the birds are coming to visit
 the feeder and they're flying in
they fly in and fall into the pocket. 
Between these two tram lines
 there's a lot of netting
and then we can just reach down in 
and untangle them and extract them.
That's how we do it. 
We set these nets and that
 allows us to catch these birds
and then put the passive integrated
 transponder or a PIT tag on their leg.
-[?] and this one. Here's the PIT tag.
-This PIT tag allows for our RFID feeders
to detect specific individuals 
as the PIT tag has a unique 10-digit code 
that corresponds to each unique tag 
and thus each unique bird.
-07.
-07.
-00.
-00.
-EE.
-EE.
-29.
-29.
-AB.
-AB.
-Okay. Ready?
-You want to release it. Is slow motion better?
-We can do slow motion.
-Okay.
-[laughs]
-After we've banded it 
as many chickadees as we can
the next step is just to leave the feeder 
open until we get a lot of visitation 
so birds that are coming 
and actively using the feeder. 
Birds are comfortable and when 
we have up to a hundred chickadees 
visiting one of our feeder sites 
at a given moment
that's when we actually
 turn on the RFID feeders.
We turn these on and
 we program them into all target mode
which means that any bird with a PIT tag
any chickadee with a PIT tag 
that comes and lands on a perch
one of these black perches
 allows the feeder to open. 
It has a mechanism that 
opens and closes a small door 
and gives chickadees access to a seed inside. 
This mechanism can be 
a little scary at first for chickadees 
and so we actually turn on all these feeders 
and let the birds get used 
to this opening and closing
of the feeders before we move
 to the next stage of our experiment.
When we're finally ready 
and these birds are still visiting. 
They're habituated to 
the opening and closing mechanism.
That's when we actually begin 
our memory and learning experiment. 
There's eight feeders in an array 
and we have several hundred
 birds visiting each location. 
Each one of these are equipped 
with a circuit board which has memory. 
We're allowed to program into this 
internal memory a specific set of individuals 
that are visiting the feeder
so a specific set of birds. 
Those feeders will then only open to those birds
they're saved in those memories.
We can distribute those several hundred
 birds across these eight different feeders.
When these specific birds come to the feeder
every single feeder 
was opening to them before
and now only the specific feeders assigned 
to them will open and give them access to seeds.
This is crucial because when a chickadee comes
for the first time and has
 its specific target feeder program
the chickadee will come 
and maybe land on a different feeder
that it's normally been 
rewarded at previously.
It won't open for it. 
This chickadee will then fly around the array
and sample other feeders
 until it finds the specific feeder 
within the eight that opens for it.
Then, it will extract the seed and fly away.
When it comes back for a second trial
when it comes back to find it again
if it directly flies to that feeder
 that it learned opens for it
that means that it's a very superior bird 
and that it's using its memory
its previous experience to find
 that same rewarding location again. 
How many errors it makes when 
it's visiting our array each time allows us 
to measure the speed 
of learning and measure
how well these birds are learning 
and memorizing these
 specific locations in the woods.
[music]
-Well, after two years of studying memory
 in chickadees that we mark with PIT tags
we did indeed find that chickadees
that had better spatial
 memory survived better 
and chickadees that did not have 
very good memory did end up dying. 
This is a very exciting result 
because it's been hypothesized for years
but for the first time, we actually
 were able to show this in the wild
by measuring cognition of these birds 
in wild conditions exactly
 where they are living.
We also found
which also supports the same findings
is that adult birds show better 
memory than juvenile birds
which is interesting. 
It's what we call the age-plus comparison. 
You could have more juveniles initially. 
They have a lot of variation
many of them are good
many of them have bad, but then
the ones that are not good at memory will die
so the birds becoming adults
 by default will have better memory.
We will detect it if we compare different ages.
Finally, we'll also show that birds don't change
 their memory performance between years.
We found that the birds, when we tested them
when they were one-year-old
 showed the same performance
when they were two-year-olds.
Suggesting then that 
learning between the years 
and that we too measure is a relevant trait
or a special memory that birds
 likely use to find their caches.
Here it is. That's the end 
of one part of our study.
-We hope to keep this
 research project ongoing. 
We're going to keep tracking
 these individuals for years to come. 
They're excited to keep
 solving the chickadee puzzle.
-If you see these birds 
with PIT tags, please let us know.
-Let's go.
-Let's go.
[engine revving]
[music]
-The bird that we study is locally famous.
It's known as the cheeseburger bird 
because that's its normal song. 
It sounds like he's saying cheeseburger. 
The male singing in the spring
which they wouldn't be singing now
but he would say [whistling]
so "Cheeseburger", as he tries to find a mate.
