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Birds

Hooked beak

for tearing flesh

Bones are

hidden beneath

feathers and

muscle on the

leading edge

of the wing

Wing feathers
are long and
broad to enable
soaring flight

Tail feathers are

used for braking

and as a rudder,

letting the eagle

slow down or

turn suddenly

Sharp talons

grab prey firmly

NESTS

GOLDEN EAGLE IN FLIGHT 1

Birds of prey are powerful fliers

and have superb eyesight,

allowing them to spot prey on

the ground even when they are

hundreds of metres up in the air.

BIRD CLASSIFICATION

• With around 9,500 species,
  birds make up the second
  largest vertebrate class after
  fish. They are also the most
  widespread, occurring from
  the polar ice caps to the most
  isolated islands.
  
  
  • Birds are classified into 27
    different orders.
  
  
  • The largest order, Passeriformes
    or perching birds, includes well
    over half of all bird species.
  
  
  • The smallest order has just
    one species – the ostrich.
  
  
  
  

Nests are safe places where birds lay their

eggs and rear their young. Adult birds do

not normally sleep in nests, but roost in

trees or other sheltered spots. Different

species of bird build different types of nest.

Some are simple, others extremely complex.

1 BONE STRUCTURE

Birds‘ bones are honeycombed

with holes which reduce weight

but not strength. Beaks are also

lighter than jaws with teeth.

4 SKILLED NEST-BUILDER

African weaver birds construct

elaborate nests by knotting

stems of grass together. Some

weaver birds nest together in

huge hanging structures that

are occupied all year round.

GUILLEMOT EGG 3

Guillemots lay their eggs

on narrow cliff ledges. The

pointed shape enables the egg to

roll safely round in a circle if knocked.

HOW ARE BIRDS’ BODIES DESIGNED FOR FLIGHT?

Birds have evolved many features to make flight

possible. The skeleton is strong but light, with a large

breastbone to support powerful muscles for flapping

wings up and down. The wings themselves are curved

on top, flatter beneath – air travels faster over the

upper surface, producing lift. The long tail helps with

direction and balance, while strong legs assist take-off.

CAN ANY YOUNG BIRDS LOOK AFTER THEMSELVES?

The young of ground-nesting birds, such as ducks and

geese, hatch out as fluffy chicks, which are soon able

to stand and fend for themselves. Most birds, however,

hatch out blind, bald, and helpless. Their parents bring

them food for several weeks while their feathers

sprout and they grow strong enough to leave the nest.

WHY DO BIRDS NEST IN TREES?

Many birds nest in trees because eggs laid there will

be out of reach of many predators. Some birds nest in

other inaccessible places. For example, swallows and

martins nest under the eaves of houses, and storks on

rooftops. Many sea birds, such as gulls, nest on cliff

ledges, while kingfishers dig burrows in riverbanks.

Birds have wings covered with feathers, which allow most

of them to fly. Most birds also have extremely good eyesight

and hearing. They reproduce by laying eggs, and many build

. NESTS to rear their young. Some birds fly on long

journeys called^. MIGRATIONS to breed or find food.