A goose (plural geese) is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera Anser (the grey geese), Branta (the black geese), and Chen (which includes the white geese) the latter being commonly placed within the genus Anser. Some other birds, mostly related to the shelducks, have "goose" as part of their names. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are smaller. The term "goose" is more properly used for a female bird, while "gander" refers specifically to a male one. Young birds before fledging are called goslings. The collective noun for a group of geese on the ground is a gaggle when in flight, they are called a skein, a team, or a wedge when flying close together, they are called a plump.