What is a bird ?

Birds are vertebrates whose bodies are covered with feathers; they have a beak like a horny sheath. Their clavicles are fused, forming a single bone called a furcula or ‘little fork’.

The evolutionary history of birds is still quite vague and probably dates from around 150 to 160 million years ago. These days, their closest relatives are crocodilians.

Their forelimbs turned backwards to become wings, and feathers formed a support-ive surface which enabled flapping flight. Nevertheless, some species later lost this ability, and developed other features allowing them to run or swim.

All birds are warm-blooded, lay eggs and often display extremely complex behaviour.