There are about 9,000 different species of bird, and they all lay eggs. Baby birds called chicks come from eggs. Birds are the only animals that have feathers. All birds have wings and most birds can fly.
Courtship is when male birds try to find female birds that they can mate with. Male birds do many different things to find a mate. Some males show females their colors. The male frigate bird pushes his red throat out like a balloon. The blue-footed booby shows his big blue feet.
Songbirds sing for their females, and the bower bird builds a special place with twigs and puts bright colored things in it so that it looks pretty.
Birds work very hard to build nests — special homes where they can keep their eggs and chicks safe and warm. They find grass, mud, and twigs, and they push them together. Many birds build nests in high places like trees and cliffs. Others build them on the ground. These birds are usually brown and speckled, so they are well camouflaged.
The female bird lays her eggs in the nest. Then the female or the male sits on the eggs to keep them warm. When the chick is ready to hatch, it breaks the shell with a special ‘tooth’ on its beak.
Cuckoos lay their eggs in other birds’ nests. When the baby cuckoo hatches, it pushes the other eggs or chicks out of the nest so that it can have more food. It often grows much, much bigger than the adult bird that is feeding it!
Ostrich eggs are the biggest bird eggs, and they can weight about 2 kilograms. If you stand on one, it will not break!
Many chicks have no feathers, and they can’t see or move when they hatch, but some can run, swim, and find food. Birds feed their chicks and keep them safe until they can care for themselves. Birds often have to fly to and from the nest hundreds of times a day to bring enough food for their chicks.
Some small birds can fly just two weeks after they hatch, but bigger birds take longer. Chicks watch their parents and learn to fly, feed, sing, and keep safe. Some baby birds do not become adults for months or even years.
Many birds that migrate every year have to make long, dangerous journeys when they are still very young. These birds fly to warmer places for winter and come back to their breeding places for summer.