Birds are believed to have descended from dinosaurs. It is known that there were winged dinosaurs with feathers, for example.

Birds can fly because they have very thin bones. Unlike human bones, which are thick and heavy, bird bones are thin and light. This means they can move their wings easily and they do not have to lift a heavy body.

Birds lay eggs, usually in nests, and often sit on the eggs to keep them at just the right temperature so they hatch properly. Then the chicks are fed by one or both parents until they are old enough to find food for themselves.

Birds nest in holes in trees, in riverbanks, in holes in the ground, in nests in hedges, and all kinds of other places.