White-tailed eagle with wings spread being chased by a gull


Birds are a class of vertebrates. They are bipedal, warm-blooded, have a covering of feathers, and their front limbs are modified into wings. Some birds, such as penguins and ostriches, have lost the power of flight. All birds lay eggs. Because birds are warm-blooded, their eggs have to be incubated to keep the embryos inside warm, or they will perish.

All you need to know about British birds.

Scientific name: Aves

Rank: Class

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Map showing the distribution of the Birds taxa

The shading illustrates the diversity of this group - the darker the colour the greater the number of species. Data provided by WWF's Wildfinder.

Bird size range

A graphic illustration comparing the size of bird with humans, from largest to smallest: moa, ostrich, Gastornis, human, flamin

A comparison of bird size in relation to humans - from the 3.7m tall moa to the 12cm high robin.

BBC News about Birds

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