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A robin sits on a branch

A robin sits on a branch: birds biology

When did birds evolve?

The first birds evolved out of earlier small dinosaurs late in the Jurassic period, about 150 million years ago. At this time, most of the bigger animals on Earth were dinosaurs.

Really, dinosaurs?
The Jurassic period
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How are birds the same as dinosaurs?

a bird's nest with three small blue eggs in it

A robin’s nest with three eggs in it

Birds are like dinosaurs in many ways: they both lay eggs in nests, and they both walk mainly on their hind legs (Birds use their front legs as wings). Many dinosaurs were warm-blooded, like birds. Some dinosaurs even had feathers, like birds. Some dinosaurs had beaks, like birds, instead of teeth.

More about eggs
And about feathers
Jaws and teeth evolve

Why do birds eat bugs?

An eagle over the water

An eagle over the water

Birds ate the same things as small meat-eating dinosaurs Рworms and small insects like flies, grasshoppers, bees and mosquitoes, and meat from dead reptiles and mammals and frogs. Sea birds also ate mollusks like clams and mussels. There were a lot of bugs around in the Cretaceous period, when a lot of birds evolved. Flowering plants were evolving, and bugs evolved to eat their nectar. Then  birds evolved to eat the insects.

Flowering plants
Bees and mosquitoes
The Cretaceous period

Domesticated birds: chickens and turkeys

Most birds are still wild. But people have gradually domesticated a few types of birds. Chickens and turkeys, especially, survive mainly as farm animals today.

Chickens in Asia
Turkeys in Central America

Learn by doing – birds

Bibliography and further reading about birds:

Cells
Biology
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