Translator: Ilze Garda Reviewer: Denise RQ
I study birds.
I'm an ornithologist.
When I say that to people, they usually assume
I'm one of those crazy people that wakes up in the middle of the night,
drives across the country to see some obscure bird.
And they're right.
(Laughter)
I've done things to see birds
that many of you would not do to your parents.
I've gone out on a ship in the middle of the winter storm
to count gulls.
I've spent months on a rock in an ocean to count sea birds.
For many summers, I've woken up at 5 o'clock in the morning
to watch amazing birds - sparrows.
I do this because I really, really like birds.
I think they're beautiful, and I think they're fun.
But over years,
I've come to appreciate birds from a different perspective,
from a perspective that's more than just fun.
Because, when you take a closer look at birds,
when you spend more than just a second
looking at the same individual, the same species,
you start to see these amazing parallels between birds and us.
You start to realize that we can study birds
to answer fundamental questions about our behavior, ourselves,
questions that apply to us.
This is important because there are many questions
about our behavior, about how we are built
that we can't answer using ourselves
because of logistical or ethical challenges.
Instead, we use model organisms.
For example, to find out how cancer works, we use mice
because mouse cells and human cells, mouse organs and our organs
work in much the same way.
By studying mice, we can find out treatments for our diseases.
But we can't use mice to study everything in humans.
And so today, I will show you that birds are a great model system
for questions that apply to us about our behavior, our physiology.
Birds are a great model for behavior
because their social system is really similar to ours.
90% of birds form pairs.
They have something that we could call a family.
In 85% of bird species, both mom and dad take care of the babies,
much the same way as we do,
and this makes birds more similar to us than many mammals
because biparental care is rather rare in animal kingdom.
Birds have personalities.
They vary tremendously in how aggressive they are,
how sociable they are, how daring they are,
much the same way as we do.
Birds are also great models for physiology
because bird hormones and our hormones are really similar,
and our nervous systems work in the same way.
To demonstrate this,
I will tell you three stories
from my research and my colleagues' research,
I will show you that we can study birds
to answer fundamental questions about empathy, sex, and stress.
Empathy is a very important human emotion,
it's the ability to put ourselves in other's shoes,
understand things from other's perspective.
Empathy makes us who we are, it allows us to forgive.
Have you ever wondered why we have empathy?
Why care about others?
Because the principle of natural selection
seems to suggest that we should all be selfish,
we should not care about others, but yet we do.
Why?
We can ask this question in birds.
Birds do this thing called mobbing
where they come help each other to drive off predators.
This cute European songbird, the pied flycatcher,
helps its neighbors
to drive off predators when they attack their nests.
But they are calculating little animals:
they only help each other if they are being helped back.
It is a famous strategy in game theory
that's called tit for tat.
But this strategy is also vulnerable to end up in a complete mess
because somebody, by accident, at some point, will drop the ball,
fail to cooperate,
and this whole cooperation will stop.
Yet, these birds keep cooperating.
How do they do it?
A Latvian professor Indriķis Krams and I showed
that pied flycatchers maintain cooperation
because they are able to understand each other's circumstances.
They show empathy.
This is how it works.
The bird is attacked, it needs help from its neighbors.
They usually come to help, and everything is fine,
as this bird will afterwards cooperate back.
But sometimes, the help does not come.
If you're playing a strict game of tit for tat,
this would lead to a breakdown of cooperation
because this animal would never ever talk to these guys again.
But these pied flycatchers sometimes bend these rules.
They forgive birds that couldn't come to help
because of honest reasons, such as they just weren't at home,
but they refuse to cooperate
with birds that didn't help even if they were able to.
So empathy, the ability to forgive some, but not all,
enables these birds to keep cooperation going.
And though human empathy surely is a much more complicated emotion,
our research shows that it's also very ancient,
that it's shared between birds and humans,
and it likely evolved to help us cooperate.
Birds can teach us about our sexual behavior.
Similarly to humans, birds appear monogamous,
which means that they form pairs, they have something like a family,
but they also cheat, have sex with other individuals all the time,
this happens around 30% of time.
So why is that?
Why do people and why do birds cheat?
(Laughter)
In terms of evolution, the answer may be straight forward for males
because the more you cheat, the more females you have sex with,
the more children you have,
and so you pass your genes on to the next generation more successfully.
But for females, the answer is less straight forward.
In most species, the number of children a female can have is limited,
it's constrained to a certain number.
So why spend time and energy
trying to find different fathers for your children
if you have a perfectly willing partner at home?
You can imagine
how hard it would be to study this question in humans.
Instead, we use a large population of this gray brown American sparrow
called dark-eyed junco.
We catch these birds that are cheating
much the same way we catch people who are cheating:
we use their DNA.
We compare the DNA
between the moms, their babies, and all the males in the population,
year after year after year.
We follow the babies, we follow the babies' babies.
The human equivalent of this
would be to study an entire town for something like 200 years;
it's a pretty hard task.
So using these techniques,
Professor Ellen Ketterson and Dr. Nicole Gerlach,
with whom I've had the pleasure to work with at the Indiana University,
showed that cheating can be advantageous,
that birds that cheat have higher evolutionary fitness.
And this is why.
Imagine two females:
one female, the faithful one, has sex only with her partner,
the other, the promiscuous female,
has sex with her partner, but also cheats with this other sexy dude,
and sexy in this species means older, bigger, and this big white tale.
They both have the same number of babies because they can only lay four eggs.
But what the promiscuous female has that the faithful one does not
is this son that was fathered in that promiscuous mating,
and this son grows up to be just like his dad:
he has a lot of sex with a lot of females and produces a lot of children.
And the result of this thing is that the promiscuous female
has way more grandchildren than the faithful one.
This is called the good genes hypothesis.
This shows that cheating can have an evolutionary advantage,
that it's an evolved behavior.
I'm not saying you should go out and cheat tonight,
that would be kind of bad,
but, if you do, you might just end up with really sexy children.
(Laughter)
So the desire to have sex does not stand alone,
there are many things that affect our desire to reproduce,
and one of the biggest ones is stress.
It's a big thing in our lives.
When I am stressed, like before this TEDx talk,
I don't want to go party, I don't want to have sex,
and I'm sure many people in this audience and in the backstage
feel the same way.
So why? How does stress affect our reproduction?
Why does this happen?
We can ask this thing in birds.
We can ask this in birds
because many aspects of stress and reproduction
are regulated by hormones,
and birds and humans share hormones that are nearly identical.
We both have testosterone that is produced in our gonads,
that regulates, in both males and females, sexual behavior and development.
We both have glucocorticoids,
stress hormones that are produced in the adrenal glands here.
We also share estrogen, progesterone, oxytocin, adrenaline,
and the list goes on and on and on,
so our hormones, these complicated, intricate systems, are nearly identical.
They are probably so ancient that they were present in dinosaurs.
So we can use these parallels, we can capitalize on these similarities
to study birds to answer questions about ourselves,
about how stress affects reproduction.
A good candidate for this effect is testosterone,
because testosterone is so important in reproduction.
I asked these brown American sparrows how the stress affects testosterone.
And it has big effects.
When you stress these birds out, when their life is in danger,
when they perceive that their life is threatened,
they reduce their testosterone levels, and then they jump up.
This might not be bad, this might actually be good
because maybe it is better to focus your energy responding to stress
rather than being distracted by sex.
But for some of us, stress is not just this one time thing,
it's a constant occurrence, we are stressed day after day after day.
What happens to our testosterone?
I asked this in these birds, and I showed that if you develop
in a really traumatic, nerve-racking environment,
you have lower testosterone, generally, and that's bad,
but you're also less sensitive to stress, and that's a good thing.
So my research shows that stress in development
can have major effects on your testosterone.
By understanding the mechanisms
by which stress affects our lives, by which stress affects reproduction,
we can move towards cures and solutions for problems that affect us,
our own problems and diseases.
So we can learn from birds about stress.
You can't use birds to study everything.
It wouldn't make sense to study cancer in birds
because their organs are a little different from ours.
But because their physiological and nervous systems are so similar to us,
because their behavior, their social behavior,
is so similar to ours,
we can use birds to ask basic questions
about empathy, about cooperation, stress, sex, and many more things.
For example, we can study birds to study personalities.
Why are there so many personalities? How are they regulated?
We can study birds
to understand how cities affect our behavior and our hormones.
We can study birds to understand how parenting works
because there aren't many animals
where both mom and dad take care of the babies.
This cover is from the Science magazine,
one of the most famous and influential magazines in science.
In this edition, scientists showed
that we can learn from birds about speech development
because song development in birds and development of speech in humans
share many parallels at the physiological level.
So there is much more to birds than just their looks.
As ornithologists - we're crazy people -
we wake up at 5 o'clock in the morning and drive across the country
not only because we want to marvel
at the birds, at their beauty, and how fun they are
but also because we want to learn fundamental truths about ourselves,
abut how nature works, about how evolution works.
In fact, one of the birds that tells the most about ourselves
is this seemingly unremarkable gray brown American sparrow.
But when you take a look at it, when you spend some time looking at it,
you realize how much you can learn from it.
So next time you see a bird, ask yourself,
"Can I learn something from you?"
Thank you.
(Applause)