Birds
Birds are one of six classes in the animal kingdom. This group of endothermic vertebrates are characterised by feathers, toothless beaks and hard shelled eggs. There is estimated to be roughly 9000 – 10000 extant species of bird, with over 60 of these lacking the ability to fly, a characterised often synonymous with birds, for example the ostrich and the penguin.

How the battle of the sexes left the duck with an awkwardly long, corkscrew-shaped penis

Both male and female ducks have evolved bizarre genitals.
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World's weirdest animals: Meet the great-eared 'goatsucker' nightjar bird

These nocturnal birds have ear-like feathery tufts on their heads, excellent night vision and a call which is said to be jarring.
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Flamingoes aren't born pink. Here’s the (very bizarre) reason they take on that colour 

As shown in BBC's Life in Colour, flamingos aren't born with that colour.
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Where does the cuckoo learn its terrible behaviour?

The cuckoo tricks other birds into raising its chicks at the expense of the foster parents' own brood.
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Protective parent in a dramatic dive swoops in to win Bird Photographer of the Year

All the latest winners from the annual Bird Photographer of the Year Competition.
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Big city life makes birds better dads, suggests new study

Urbanisation is having a surprising affect on the local bird population.
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In pictures: The rare green avadavat birds fighting to survive

Hidden in the mountains of northwest India, a beautiful songbird fights for survival.
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