Goose — The word goose (plural: geese) is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller.
A number of other waterbirds, mostly related to the shelducks, have “goose” as part of their name.
The term goose applies to the female in particular while gander applies to the male in particular. Young birds before fledging are called goslings. The collective noun for 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.
There are three living genera of true geese: Anser, grey geese, including the domesticated goose and the Swan Goose; Chen, white geese; and Branta, black geese, such as the Canada goose.
Two genera of “geese” are only tentatively placed in the Anserinae; they may belong to the shelducks or form a subfamily on their own: Cereopsis, the Cape Barren Goose, and Cnemiornis, the prehistoric New Zealand Goose.
Either these or, more probably, the goose-like Coscoroba Swan is the closest living relative of the true geese.
Geese are monogamous, living in permanent pairs throughout the year; however, unlike most other permanently monogamous animals, they are territorial only during the short nesting season. Paired geese are more dominant and feed more, two factors that result in more young.