I'm Sahas Barve.

I'm an evolutionary ecologist and ornithologist

at the Smithsonian National Museum of Natural History.

Today, I'm here to answer your questions from Twitter.

This is Bird Support.

[upbeat music]

This question is from jehzoo.

How do messenger pigeons work

do they have google maps or?

Some pigeons have very strong abilities

to detect magnetic fields,

but they also remember landmarks really well.

A lot of homing pigeons also have

what is called magnetite in their beaks

and magnetoreceptors in their nervous system or brains.

This magnetite basically helps them

to orient in the right direction.

So, even if they can't see the sun,

if it's really cloudy and windy,

and they can't orient themselves,

they will know which way is north,

or east, or west, and south,

because of this really cool,

these magnetite particles in their beaks.

The next question is from WillJParker.

Jesus [beep] why are these geese so loud?

It's [beep] midnight go to sleep geese.

Geese can be loud for multiple reasons.

When they're getting ready to migrate,

they honk a lot to sort of get their crew together.

In the spring, they start pairing up,

and they vocalize with each other

to sort of strengthen the pair bond.

But they also then honk together

to keep other pairs of geese away from their territory.

They'll probably honk at you very loudly,

or even may run up to you

or charge you with their wings open

if you're too close to their eggs or babies.

A question from imari.

Wait how do birds have sex?

Most birds have sex by what is called cloacal kissing.

Birds have a common orifice for pooping and peeing,

and basically having sex.

And so, first the males and females line up their orifice

and a male transfers the sperm into the female's cloaca.

So, that's true for most birds.

But some male birds, like ostriches,

have what pretty much looks like a penis.

It's often called cloacal protuberance.

They insert that penis into the female's cloaca

to transfer the sperm.

Ducks have corkscrew-shaped penises.

They go into the female's cloaca,

which is also reverse corkscrew-shaped.

Because there is so many forced matings

in several duck species,

mallards being the most common example,

females actually also have blind alleys

that don't lead up to their ovaries and eggs.

And so, if the female doesn't want to mate with a male

that's sort of forcing himself on her,

she can just get him to deposit the sperm

in one of these blind alleys,

where his sperm will never be able to fertilize the eggs.

The next question is from br0k3nhalos.

How do owls turn their heads so far around

is their spine in the center of their neck?

Owls have this crazy ability to turn their heads

almost up to 270 degrees, which is absolutely nuts.

And here's a specimen of a Northern Pygmy-Owl

that is showing you what it's doing.

It's actually turning its head completely around,

and that's something that you cannot do.

There are two reasons why birds

evolved the ability to do that.

The first is that birds cannot move their eyes

in their own sockets.

So, I can follow my finger without turning my head,

and that's because I can move my eyes in my sockets.

Birds can't do that.

And so, they have to move their head

every time they want to follow another object.

The other reason,

when I turn my head all the way to the back,

after a bit of time,

I'm going to cut off the blood supply to my brain.

It's not gonna be very nice in a few seconds

because I'll probably pass out if I keep doing that.

But owls have evolved this really cool

blood supply network that actually compensates.

Other blood vessels take over

and keep supplying blood to the bird's brain.

This bird is also really cool

because it has these markings

that look like eyes at the back of its head.

A lot of owls around the world have those markings,

and they are also supposed to be

an anti-predatory strategy.

Constantly saying, Hey, I'm looking at you,

even if they're not.

By FunkyDiabetic1,

How do birds all know where to go at the exact same time?

The simple answer is they're just watching their neighbors.

These big murmurations of starlings,

that you may have seen videos of,

do these really cool formations in the air.

Well, we don't know exactly why they do that,

but they are doing

what the next few birds around them are doing.

So, you'll see a few birds turn,

and that sort of wave goes through the whole flock.

They are not that coordinated

as a whole flock of a thousand birds,

but they coordinate with their immediate neighbors

that are flying around them.

When geese or starks fly in a V,

there is some thermodynamic advantage,

and the bird in the front is working the hardest.

And often, the bird in the front will give up

and go back in line and another bird will take its place.

Birds sort of coordinate who is doing all the work

when they're flying

to make everyone's energy use more efficient.

Next up from locallystupid.

How do birds not get cold...

I feel like they need a jacket.

So, most birds have a feather that is part down.

These fuzzy, non-interlocking barbs

that basically catch air close to the bird's body,

very similar to mammal fur.

Penguins live in really cold environments

and they have extremely dense feathers.

There are other birds that live

in very cold environments as well.

In northern Canada, there are chickadees that live in

negative 20 degrees outside,

and the chickadee is the same weight

as a couple teaspoons of sugar.

The feathers in your down jackets come from geese and ducks.

And so, we have actually used their feathers

to keep us warm now.

Next up is a question from tonysabad.

What's the smartest bird?

I bet you it's none of them.

New Caledonian crows are supposedly wicked smart

because they can design their own tools,

and you can give it a stick and it will make it into a tool

that it will use then to get to a treat

that you set up for it.

Also, birds are really smart

because they can fly from Alaska to New Zealand,

and find the exact same spot that they found last year.

Try going anywhere without Google Maps yourself,

let alone across continents.

CbdElizabeth, Do all birds lay unfertilized eggs

the way chickens do?

Do wild songbirds lay empty eggs?

Most birds don't want to lay unfertilized eggs

because unfertilized eggs is a lot of energy and resources.

Some birds lay eggs

that are as much as 20% of the bird's body.

There are birds that lay unfertilized eggs,

but as part of a bigger clutch of eggs are fertilized eggs.

Chickens that lay unfertilized eggs

have been manipulated hormonally, generally,

to produce eggs that are unfertilized.

Do wild birds, wild songbirds lay empty eggs?

If you mean something like a ping pong ball,

then they don't because the eggshell

is actually a covering that goes onto an embryo.

So, inside of the egg forms first,

and the eggshell is sort of sprayed on around it

and then hardens.

They can't just form the outside without the inside.

So, they don't lay empty eggs.

This question is from DudasClancy.

Do bird eyes dry out as they soar through the sky?

Birds have this third eyelash

called the nictitating membrane.

It's a transparent membrane,

so birds can actually use it while they're flying.

If you watch a bird up close,

you can actually watch them use their nictitating membrane

to wink their eye close and shut.

But the nictitating membrane itself

is completely to transparent.

And so, the bird can still keep seeing when it's doing that.

Next question is by DekelDw.

Do all birds build nests?

Most birds build nests,

but several different families of birds

evolved what is called brood parasitism,

where females lay eggs in another individual's nest.

And that can be another individual of same species

or another individual of a completely different species.

Cuckoos, for example,

go and lay their eggs in the nests of other birds.

Those eggs generally hatch out earlier

and push out all the other babies.

And then, the parents end up raising just the cuckoo chick.

Quick anecdote about that is that cuckoos know

that the host birds can count.

When they go to lay their eggs,

if they find four eggs in the nest,

they will lay one egg and then take out one of the host eggs

to make sure that the host doesn't find out

that there are suddenly five eggs

when they only laid four.

Mistress_time, What the [beep] are emus.

Why do they make that sound

they're literally dinosaurs wtf.

Why the hell is there a bird that's taller than me

this isn't fair.

The emu is not even the biggest bird in the world.

So, the ostrich is bigger than the emu.

They are pretty big.

Well, I'm glad you brought up dinosaurs

because birds are in fact more closely related to dinosaurs

than any other animal that ever lived on earth.

Why are they so big?

Well, there's bunch of birds,

ostriches, emus, and cassowaries,

these three birds are really, really big.

They can be as tall as people or even bigger.

They are just an ancient lineage of birds.

Now that you know that birds are actually dinosaurs,

they're actually pretty small, right?

From hummusbeings or humusbeings.

What's the loudest bird for its size?

Two New Holland honey eaters can make quite a racket.

Loudest recorded bird is a white bellbird.

[bird screeching]

Most of their sounds they make

are above the frequencies that we can actually hear,

but they can be extremely loud.

Those birds can be louder than some planes even.

They often use that to attract mates.

From martymush,

Do birds ever know where they are actually going

when they go south or do they keep flying until it's warm.

I feel like they aren't just like

we're going to Florida pack it up.

Well, birds do know where they're going

and they'll often use the Earth's magnetism, the stars,

and several landscape features

to direct where they're going.

Birds have the ability to go across continents

and find the same patch of forest

that they spent last winter in.

GPS trackers have shown that some birds,

like the bar-tailed godwit,

fly non-stop for 12,000 miles from Alaska to New Zealand

and find the exact same patch of wetland

that they used the previous winter.

eelaizha, Are there any birds with teeth?

That's one of the weird mysteries of bird evolution.

Before the dinosaurs went extinct,

there were a lot of birds with teeth.

And then, after that, there are no birds with teeth.

But there is no real reason

why there are no birds with teeth today.

None of them, for some reason,

survived same apocalypse that wiped out the dinosaurs.

From rainelew3, How do birds fly in the rain

explain it to me now.

Birds fly in the rain

just like they fly in any other weather.

Bird feathers have highly water-resistant parts

called the pennaceous barb,

which stops the water from actually going in

and soaking the rest of the bird.

When they take a bath, they can dunk themselves in water.

Many ducks, you may have seen, on the water

and they emerge without getting wet.

It's because they're wearing a rain shell the whole time.

imReactss, Do birds ever fly just for fun

or are they always on some sort of a mission?

Just like you and me, many birds play.

Crows and ravens will often play

and you will see them doing these really cool tumbling dives

through the air.

Crows and ravens are a good example.

They'll fly to have a game with their flock mates,

and they will fly around just when it's really windy

or, I don't know, just for the fun of it.

Ziahxt, Bro, how do owls not produce sound while flying?

That's a great question.

Owls have really cool adaptations

to reduce the amount of sound they make.

Owls are generally nocturnal,

and most animals that are nocturnal

have a really good sense of hearing.

Owls have evolved this way to sort of cancel

the amount of noise that they're making

when they're flying from the flapping

by the cool feathers they have.

So, the owl feathers,

the ends of the barbs have combs or little brushes

that basically break up the air in a way

that it doesn't produce a sound when it's flying.

Not all owls have that, but most owls have that.

From @mkangwenyi, Is there a Shazam for bird call?

You can download an app called Merlin,

and then record a bird call,

and then Merlin will help you ID it

and tell you what bird it is.

But you can generally filter down from all the birds

that are in your field guide to just a few species,

based on the size of the bird, the habitat you're seeing,

and where you are seeing the bird on earth.

That's something that you learn to do

from when you start birding.

Next question is from AuthorRKK.

How do birds learn how to use tools?

I'm curious.

Several birds show tool use.

Egyptian vultures will use giant rocks

to smash open ostrich eggs.

Darwin's finches on the Galapagos Islands

will use little sticks as spears to fish out caterpillars

and beetle larvae that are hiding

underneath the bark of plants.

We don't know how birds learn to use tools.

They definitely watch others as they make tools.

We know this from New Caledonian crows,

and we know this from ravens, and from keas,

that they are very, very good social learners.

You and I learn new tricks from watching someone else do it.

Birds, they'll watch another bird.

Study what the other bird is doing.

Especially, if the tool the other bird is using

ends up in them getting a treat,

then they'll definitely be very, very careful

about learning that and then go try it themselves.

By Ubermoogle,

Curious amateur #birding question:

Is beak color variable within species,

or is it a defining character?

Beak color changes both within species

and within an individual also.

European starlings will actually change

the color of their beak in the summer,

then in the winter.

And color of the beak is also driven

by some of the same compounds

that drive the color of feathers.

The variation in bird beak color within a species

is often used to identify different populations

from each other.

SUEtheTrex, Ornithology question:

Do birds in tropical zones migrate like they do

in temperate climates?

How can you tell what species will be where

throughout the year?

Many birds will often migrate just to find food.

So, a lot of birds will fly between areas with high rainfall

to areas with low rainfall.

This includes a lot of birds in Australia

and a lot of birds in Africa

that follow the rain clouds across the continent.

Rain generally produces a new flush of vegetation,

which produces a new flush of insects

that these birds feed on.

Parrots will follow fruiting cycles

of different species of trees

just because they know that their favorite fruit

will be fruiting in that area.

How can you tell what species will be where

throughout the year?

Your bird guide will generally tell you

whether a bird is a year-round resident

or is found only in the winter or only in the summer.

That's something for you to find out as well.

You can go birding and make a list of birds that you see.

At the end of one entire calendar year of birding,

you will know what birds you see throughout the year.

This question comes from drdelarocker.

Ornithology question!

Do birds breed inter-species?

My wife and I were talking about dogs and mutts,

and we realized that we don't know

if there's a bird equivalent.

Can an albatross mate with a wren or something like that?

Two breeds of dogs,

even a Great Dane breeding with a Chihuahua,

is the same species breeding with each other.

An albatross and a wren,

probably as distantly related to each other

as a human and a goat are.

There are many species of birds

that do hybridize with other species,

but those are very closely related to each other.

A good example,

maybe a wolf and a coyote breeding with each other.

That happens pretty regularly in nature.

Just because they're birds

doesn't mean that they can mate with each other.

Although, closely related species will often hybridize

with each other to produce offspring.

I enjoyed answering your questions today

and I hope you learned a little more about birds,

and appreciate birds a little more.

Happy birding.