Birds range in size from the tiny hummingbird? to the large ostrich and emu?. Flightless birds include the penguin, ostrich, and the extinct dodo. Birds are a very differientiated class with some feeding on nectar, seed, insects, rodents, fish, carrion, other birds. Some birds are nocturnal. Some birds migrate long distances to utilize marginal habitats while others spend almost all their time at sea.
Birds are an important food source for humans. This comes mainly from chicken?s and chicken eggs although goose?, pheasant?, duck?, emu?, ostrich, pigeon?, grouse?, quail, dove?, and others are utilized. At one time swan? and songbirds were delicacies of the rich and powerful although these are generally protected now.
[Homing pigeons]? are used to carry messages and the honeycreeper? leads some Africans to honey. Colorful tropical birds are often kept as pets although this has lead to smuggling of some endangered species.
See also