birds come in a huge range of colours. these colours can be useful to a bird in two ways. camouflage colours help to hide the bird, and bright colours identify the bird to others of the same species. often the male is brightly coloured while the female is camouflaged. the logic is as follows: the female carries the "precious package" of developing eggs. the male has to defend a territory, and the function of his colour and song is to let others know that "this place is occupied".