The New Childrens Encyclopedia

Birds

There are around 9,700 species

of bird. Like mammals, they are

warm-blooded vertebrates, but

unlike most mammals, they lay

eggs, their bodies are covered in

feathers, and most can fly.

FEATHERS FOR FLIGHT

A bird’s feathers not only help to keep the

bird warm, but also play an important role in

flight by giving the wings and tail the correct

shape. Feathers are made of a substance called

keratin—the same protein found in your

hair and fingernails.

Bird bones

Most animal bones are filled with spongy

marrow, but bird bones are hollow, which

makes them light. They are also strong,

thanks to the supporting struts inside.

Smaller than flight

feathers, contour

feathers give the bird its

streamlined body shape

in flight.

Under the contour

feathers on the bird’s

body, a layer of short,

fluffy down feathers

keeps the bird warm.

The bird uses its

tail feathers as both

brake and rudder.

Bill shapes

Birds have no teeth or jaws.

Instead, they have a bill made of

tough, horny keratin. The bill serves

many purposes: it can be a deadly

weapon for stabbing and tearing,

a tool for probing, crushing, or

drilling, and a delicate filter. Most

birds also use their bills for grooming.

Male common ostriches

Struthio camelus

All birds lay eggs.

One reason why is that the

female would struggle to fly

with a brood of heavy chicks

developing inside her. Most

birds incubate their eggs by

sitting on them. Mother

birds usually lay a single

egg at a sitting.

Most birds have excellent

eyesight. Hawks such as

this one can spy prey from

great distances.

Not all birds fly. Flightlessness can

be a feature of birds that have few

natural predators, such as the New

Zealand kiwi. Flying would use a

vast amount of energy in very large

birds such as ostriches, rheas,

emus, and cassowaries. Instead,

they invest their energy in running

fast. They also grow too large for

most predators to tackle.

FLIGHTLESS BIRDS

Long, stiff flight feathers

give wings the shape needed

to create lift.

Birds use their talons as

weapons and to help them

grip perches. Water birds

have webbed toes to help

them swim efficiently.

Red-tailed hawk

Buteo jamaicensis

LIVING WORLD

W

OW!

Woodpecker

Barbet

Puff bird

Chisel-shaped

bill

Conical

bill

Sharp,

slim bill

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