Why do birds moult?
A Birds grow new feathers in place of old ones. The process is called moulting. In the winter season, they grow a thick coat of feathers which keep them warm. During the summer these feathers fall off and new, colourful ones take their place. This is to attract mates for breeding. Except for ducks most birds lose their flight feathers gradually. Ducks lose them all at the same time.
