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FIND OUT MORE. Reproduction 101 • Vertebrates 102

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FOOT SHAPES

A LONG JOURNEY 3

The ruby-throated hummingbird

migrates thousands of kilometres

every year. As well as nectar, this

bird feeds on insects. In the North

American winter, both of these

foods dry up, so the bird flies south

to Central America, to find food. In

spring, it flies back north to breed.

MIGRATION

1 FEATHER TYPES

Birds have three types of

feather. Contour feathers cover

the body, while down feathers

are fluffy to provide warmth.

FLIGHT

FEATHER

CHESTNUT-MANDIBLED TOUCAN 3

Many birds have extremely bright

feathers. These are often grown by

males to attract mates but sometimes,

as with toucans, both sexes have them.

Autumn route

southwards to

Central America

RUBY-THROATED

HUMMINGBIRD

Hummingbird

is little bigger

than a thumb

Birds’ feet are shaped to help them move in their particular habitat.

The jacana’s long toes help it to walk on floating water plants without

sinking. Ostriches’ hoof-like toes help with running, and ducks’ webbed

feet with swimming. Eagles’ talons are designed to seize prey, and the

feet of perching birds, such as pipits, lock around twigs.

4 FEATHER STRUCTURE

Strands called barbs branch from

the central shaft. These bear even

thinner barbules, with toothed

edges that zip together.

WHAT DO BIRDS EAT?

Birds eat a wide range of plant and animal foods.

Some feed on specific parts of plants, such as fruit,

seeds, or nectar. Others are predators. Hawks, owls,

and eagles catch smaller creatures such as rodents.

Many sea birds feed on fish. Some shore birds have

long beaks to probe the mud for worms.

CAN ALL BIRDS FLY?

Some island birds, such as New Zealand’s kiwis, lost

the ability to fly because their islands had few

predators. Large flightless birds such as ostriches,

emus, and rheas are strong runners. Penguins cannot

fly, but are expert at swimming and diving.

HOW DO BIRDS KNOW WHEN TO MIGRATE?

Changing temperatures and daylight are thought to

trigger bird migrations. In some species, the young

follow their parents and learn the way from them.

Others set off alone, guided by instinct. Birds navigate

by the position of the Sun, Moon, stars, and physical

landmarks. Some can sense the Earth’s magnetic field.

HOW DO FEATHERS HELP BIRDS FLY?

Feathers on a bird’s wings provide a lightweight but

solid surface to push against the air. As the wing flaps

downward, they mesh together, then part to allow air

through as it sweeps upward again. As well as allowing

it to fly, a bird’s feathers keep it warm and dry.

DO OTHER ANIMALS MIGRATE?

Many kinds of animals migrate, from

mammals, reptiles, and amphibians to crustaceans,

fish, and insects. Reindeer move across the Arctic

tundra and wildebeest cross the African plains to find

fresh grazing. In the oceans, blue and grey whales

swim from polar seas to mate in the tropics.

Many birds fly long distances on yearly

migrations to find food, avoid drought or

winter chill, or reach sheltered spots to rear

their young. In spring, many fly to cooler

regions where food is abundant in summer.

They return to warmer lands for winter.

Serrated beak for

slicing through fruit

DOWN

FEATHER

CONTOUR

FEATHER

WATTLED

JACANA

OSTRICH RHEA PIPIT WOODPECKER

birds