Frequently Asked Questions about Birds

Over the years we have received many wonderful questions about birds! Here are some great examples.


How do birds fly?

  • Birds have hollow bones that are very light and strong.
  • Their feathers are light and the shape of their wings is perfect for catching the air.
  • Their lungs are great at getting oxygen and very efficient, so they can fly for very long distances without getting tired.
  • They eat lots of high-energy food.
  • Kim Bostwick, a scientist at the Cornell Lab of Ornithology explains:

    "Have you ever tried to move your open palm though the water really fast? Wide, flat objects, like your hand, or a paddle, are hard to move fast against water." It feels like the water is pushing back against you. Or have you put your hand outside the window while driving in a car and felt the air rush against it? You can see-saw your hand up and down in the wind. In both cases you can feel the water or the air push against the flat palm of your hand. But if you turn your hand sideways, you can slip your hand through the water or air easily, right?"

    "When a bird is flying, their wings are flat so that the air flows easily around it in the direction the animal flies (like your hand cutting through the water or air). However, something special and tricky happens here. As the air flows over the wing, the air flows faster over the top than the bottom because the wing is slightly curved on top. This means there will be more air on the bottom side, because the air is moving more slowly. When there is more air on the bottom that leads to a push and since the push happens against that wide flat part of the wing, this push lifts the animal. So a bird wing slices in the air in the forward direction and gets pushed up from below; the net result is a flying bird!"

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Why don’t all birds fly?

Some birds don’t fly, like penguins, ostriches, emus, kiwis, and others. It is thought that these birds lost their ability to fly because there weren’t any predators on the islands in which they evolved. There are about forty species of flightless birds, but none in North America, and New Zealand has more species than any other country!

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Why do birds have feathers?

All birds have feathers, and are the only animals that do!

  • Feathers provide protection (from weather and injury).
  • Feathers serve as insulation from cold and heat.
  • Feathers help birds attract mates.
  • Feathers wear out and get old so birds must replace them every so often. Birds molt once or twice a year depending on the species. When bird molts the old feathers will fall out or are pushed out by the growth of new feathers. Birds will generally molt before they mate. The new feathers look bright and attractive and help males attract a female.

    Did you know?
    In late summer and fall, when a bird molts, it usually grows and replaces all its feathers gradually, but sometimes a bird loses all the feathers on its head at once. The result is a very strange looking bald bird! Don’t worry--usually the feathers grow back just fine.

    Book recommendation:
    What Makes a Bird a Bird? by May Garelick (Author) and Trish Hill (illustrator)

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Why are birds colorful?

Colorful feathers serve lots of different purposes:

  • They are used to attract possible mates.
  • Colors and patterns help birds identify their own species.
  • Colors can help birds hide from predators by camouflaging them.
  • Colors are used to attract attention when courting (ie: courtship displays).
  • Colors are used to attract attention when trying to distract predators.


For example, when Killdeer see a predator near their nest, they pretend to be hurt and flop around with their wing extended. Under their wing is a patch of rusty red color (it looks like it might be bleeding). They trick predators into following them away from their nest because they’ll be easier to catch and then they quickly fly away!

Color and/patterns confuse predators. For example, one study found more Peregrine Falcons

Pigeons preening in a puddle
Colorful pigeons in a puddle.
photo © Becci Ginden-Clarke
were less able to catch pigeons that had a white patch on their rump than pigeons that did not have the white patch. The white color confused the falcons!

Interesting Note:

Odd-colored birds of a species get picked-off more easily by predators. In general, if a predator spots a bird that stands out from the rest, they will try to catch it more often than the birds that blend in.

Did you know?

The red or yellow color of a male House Finch comes from pigments that it gets in its food.

Male House Finch
photo © Adam Bender
The more pigment in the food, the redder the male. Females prefer to mate with the reddest male they can find.

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How long does it take to grow wings?

A bird grows in the egg while the parents incubate it (sit on it). It then continues to grow after hatching until it is ready to fly. Some birds can leave the nest almost instantly (as soon as they are dry after hatching), but still cannot fly until they are ready (approximately one month later). Other birds don’t leave the nest until they are ready to fly.

  • Pigeons incubate their eggs for about 18 days. Once they hatch they fly from the nest for the first time after approximately 30 days.
  • Peregrine Falcons fly about 40 days after hatching.
  • House Sparrows fly approximately 12 days after hatching.
  • Brown-headed Cowbirds fledge about 10 days after hatching.
  • Young birds don’t just have to ‘grow’ their wings, but they have to exercise them and prepare themselves to fly for the first time too. It’s not always easy!

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Do birds have belly buttons?

In the egg, there is a cord that attaches the developing embryo to the yolk sac. When the bird hatches, there is a residual scar where the cord used to be. While the bird is a nestling, you can still see what would be the avian equivalent of a belly button.

Baby Killdeer on Rock
photo © reddirtpics
However, as the bird develops, that area becomes more compact and in an adult bird there is virtually nothing to be seen of what once was the scar. So technically baby birds have belly buttons, but unlike the belly buttons of humans, these go away as they grow up.

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Do birds have ears?

Yes, you just can’t see them. The feathers that cover the ears help reduce wind noise and protect their ears.

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What do birds eat?

It depends on the bird and the time of the year. Some eat seeds, berries, fruit, insects, other birds, eggs, small mammals, fish, buds, larvae, aquatic invertebrates, acorns and other nuts, aquatic vegetation, grain, dead animals, garbage, and much more...

During the spring and summer months, most songbirds eat mainly insects and spiders. Insects are easy to find and catch, and are very nutritious. During fall and winter, however, birds that don't migrate must eat fruits and seeds to survive.

Did you know?
Cedar Waxwings can become drunk (and may even die from alcohol intoxication) after eating fermented fruit in the spring.

It's great fun to feed birds. Even in cities you may be able to attract birds to your home or apartment by feeding them. In urban areas we recommend tube feeders filled with black-oil sunflower seed (these seeds attract the greatest number of species, are nutritious, high in fat, and their small size and thin shells make them easy for small birds to handle and crack). Another favorite is nyger seed (this seed is expensive -- so feed it in a special nyger feeder so it is not wasted). This seed attracts finches.

If rodents are a problem in your neighborhood make sure that you clean-up any spilled seeds from the feeders. Place your feeders within three feet of a window (or more than 30 feet away) to reduce the number of birds that die from hitting your windows.

If you are not allowed to have feeders in your apartment building, try a natural bird feeder. Plant seed bearing plants like dwarf sunflowers, cosmos, and asters in pots (or any container that holds some soil and has holes in the bottom for drainage) and provide bright red or orange tubular flowers for hummingbirds. Learn more about feeding birds the "natural way."

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How do birds catch food?

Catching food depends on the bird. Some birds dive for fish while others hop around on lawns, eat insects that are attracted to lights in parking lots, run around on beaches with their beaks open, or hunt in other ways.

A few examples:

  • Peregrine Falcons “stoop” or dive from high altitudes, very,very fast, and come out of the dive just before crashing on the ground, with their caught prey.
  • Black-billed Magpies frequently remove ticks from deer and moose. They might eat the ticks or hide them for later.
  • Jays flick aside leaf litter with sideways swipes of bill to find food or sometimes they feed on wasp larvae by stealing the wasp nest and carrying it to a nearby perch. There, they will hold the nest with their feet and dig out the larvae with its beak.
  • California Gulls might hover over cherry trees and knock fruits to ground. Then, they fly to ground to retrieve and eat the fruits.
  • Some birds steal or pirate food from other birds or from humans.
  • Ring-billed Gulls will drop hard-to-open food while in flight to the hard ground to break it open for easier eating.
  • Some birds (crows and ravens) might drop hard nuts on the road and wait for cars to come by to crack them open.
  • Corvids (crows, ravens, jays, magpies, and nutcrackers) are clever at finding ways to get food. Watch this wonderful clip to learn more about ravens:
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How do birds eat?

It depends on the bird. They have adapted to eat lots of different things, in different places and at different heights (this helps to avoid competition for same food sources).

The size, shape and structure of a bird’s bill can tell you a lot about what that bird eats:

  • Fish-eating birds' bills (like those of loons and herons) are generally long, straight, and pointed with sharp edges for grasping or spearing their prey.
  • The beaks of birds that catch insects in the air might be short and broad and open very widely so they can swoop through the air and catch insects or they might have strong flat beaks with hooked tips to snatch them in mid-air.
  • The beaks of those birds that eat seeds are different depending on the seed that they prefer (photos). Grackles for example, have a sharp ridge on the roof of their mouth – this allows them to crack open large seeds.
  • Birds don’t have teeth. They have to grind up their food in their digestive tract. Some birds “lap-up” food with their tongues (hummingbirds).

    Did you know?
    To eat road kill, crows have to wait for something else to tear open the body or for the body to decompose and soften, since a crow’s beak isn’t usually strong enough to tear open the dead animal’s skin.

    Book recommendation: A great book about beaks is: Beaks! by Sneed B. Collard (Author) and Robin Brickman (Illustrator)

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Where do birds nest?

Mourning Dove Nest in Fern Basket
photo © readlistendream
Birds nest in all kinds of places! Where a bird builds its nest depends on the bird species.

Different species of birds nest in different kinds of habitat, at different heights, and at different times. Some birds nest in trees, bushes, the ground, or nest boxes; on balconies or cliffs; under bridges, and many more places.

For example:

  • Ovenbirds create their nests in the ground (they look like a Dutch oven – with a side entrance).
  • Pigeons make very flimsy nests (sometimes they add no nesting material at all and lay their eggs on bare ground). They might lay their eggs on an air conditioning unit on the window of a city building or on the floor of a balcony.
  • Killdeer lay their eggs right on the ground. They might lay their eggs on building rooftops, gravel parking lots, or a baseball field. Gravel rooftops attract Killdeer for nesting, but they can be dangerous.
    Killdeer Nest on Rocks
    photo © michaelcobballen
    Chicks may be unable to leave a roof because of high parapets and screened drain openings. When adults lure chicks off the roof, the chicks may die from the fall. However, some chicks have been observed leaping from a seven-story building and surviving!
  • Mourning Doves usually build their nests in trees but will build them on the ground, on window ledges, or on other man-made structures if needed. The male looks for a good place to build the nest, and once he finds one he calls the female and she either approves or disapproves. If they choose that site the male finds small twigs and delivers them individually to the female by standing on her back. She arranges them around her and uses her body to make a simple bowl. The male might make 30–40 trips at a time to give the female nesting material (normally in the early morning).
  • Hummingbirds build tiny nests. They are built by the female alone in trees (oaks, birches, pines), bushes, or other more interesting places like loops of chain or wire. Males and females only come in contact while mating. Scientists think that females find the place to build the nest, incubate the eggs, and raise their young without any help from the male.
  • American Robin Nestlings
    photo © cameronrognan
    Robins might take 5-7 days to build their first nest. Most raise a second brood during the breeding season, which can fledge just 5 weeks after the first! The second time a robin builds a nest it might take only 2-3 days, and rarely robins will have to build a third nest, which they can do in one day - but this is unusual.
  • Day length tells most birds what season it is and lets them know when it is time to migrate or to breed. Birds have to time their nesting cycle so that they will be feeding their nestlings when food is most abundant.

    Did you know?

    Yellow Warbler Feeding Cowbird Chicks
    photo © Robinsegg
    Brown-headed Cowbirds don’t make nests. Instead, they lay their eggs in the nests of other bird species, who then raise the young cowbirds.

    Book recommendation: A great book about where birds nest is: Urban Roosts: Where Birds Nest in the City by Barbara Bash (Author), Sierra Club Books (Author)

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How do birds mate?

Peregrine Falcons mating on stone building
photo © Robinsegg
Although some birds may have long and involved courtship displays, it does not take long to actually mate. Mating (the transfer of sperm from the male to the female) is very brief and takes place by the coming together of the two birds' cloacas, which function as excretory and genital organs. During the breeding season, the area around the cloaca becomes swollen and reaches its peak size when the time is just right to reproduce. Sometimes it is called a "cloacal kiss."

When bird banders catch a bird in their nets they "sex" it by blowing on the bird to part the feathers to look for a cloacal protuberance, which would only be visible in breeding male passerines.

Some birds have spectacular courtship displays. Scientists think that Bald Eagles find a mate and stay together for life unless one mate dies. When they are courting they do incredible acrobatic flight displays. One display is called the "cartwheel display": the pair fly very high, lock talons, and tumble/cartwheel back toward earth. They let go of each other only at the last moment to avoid crashing into the ground. Watch an aerial courtship display by Bald Eagles:

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How can you tell male birds from female birds?

You can’t always tell what sex a bird is by looking at it. Pigeons or starlings, for example, look almost exactly the same. In general, males are more colorful. For some birds females may be duller and more brownish. Sometimes females are smaller (but this isn’t always the case—especially for hawks where the opposite is true).

Male and Female Cowbird on Grass
photo © chardon46

One of the main causes of death in birds is predation (birds get killed by predators like cats, owls, and hawks). Different bird species have developed different ways to help minimize predation. In the case of the Northern Cardinal, these birds develop what is called "cryptic coloration." The female is not as showy as the male and blends in really well with her environment, especially when she is sitting still on the nest. Her brown color helps protect her and the eggs or young in the nest. The male, on the other hand, has the job of first attracting a female and then protecting her. For the male, it is important to stand out, so males are bright red in color.

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What are birds’ predators?

Humans, cats, chipmunks, other birds, snakes, frogs, dogs, deer, coyotes, and many more.

Killdeer Injury-feigning to lure off predators
photo © Dave W.
Book recommendation: A great book about survival is: Flute’s Journey by Lynne Cherry – A young Wood Thrush named Flute makes its first migration from its nesting ground in a Maryland forest to its winter home in Costa Rica, and back again.

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Why do some people destroy bird homes or hurt birds?

People often destroy bird habitats (including their homes) without knowing that they are doing so. Here are some ways in which humans destroy bird habitats or put birds in danger:

  • Habitat loss because of growing cities, suburbs, and development.
  • When birds are migrating long distances, sometimes they stop in one place that has just the right food for them – if people have built houses or golf courses on this ‘stop-over’ birds don’t have a place to re-fuel.
  • Windows on people’s houses or buildings confuse birds and millions crash into them and die each year. Learn how to prevent window crashes.
  • At night, lights in cities attract migrating birds, confuse them, and cause birds to crash.
  • Sometimes forests are divided up and some birds need bigger patches of woods to nest.
  • People let cats outside and they kill millions of birds (especially nesting birds)
  • People release non-native birds and they push out native species. Learn about non-natives.
  • People catch wild birds to sell.
  • Sometimes people destroy food sources.
  • Hunting (killing birds for feathers, plumes, etc.).
  • Climate change.
  • Lead poisoning, mercury poisoning.
  • Passenger Pigeons were once the most numerous bird ever, but they became extinct. Why? Humans hunted them too much and destroyed their main food source!

    Book recommendation: A great book about Passenger Pigeons is: Grandmother's Pigeon by Louise Erdrich – An eccentric grandmother leaves behind three eggs that hatch into Passenger Pigeons. Blends fantasy and science.

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