The word goose (plural: geese) is the English name for a considerable number of birds, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller.
This article deals with the true geese in the subfamily Anserinae, tribe Anserini.
A number of other waterbirds, mostly related to the shelducks, have "goose" as part of their name.
Etymology
Canada Goose (Branta canadensis) gosling
The word Goose is a direct descendant of Proto-Indo-European root, ghans. In Germanic languages, the root gave Old English gōs with the plural gēs and gandra (becoming Modern English goose, geese, and gander, respectively), New High German Gans, Gänse, and Ganter and Old Norse gās. This term also gave Lithuanian žąsìs, Irish gé (swan, from Old Irish géiss), Latin anser, Greek chēn, Albanian gatë (heron), Sanskrit hamsá, Avestan zāō, Polish gęś, Russian гусь, Czech husa, Slovak hus, and Persian ghāz.
The term goose applies to the female in particular. The word gander is used for a male in particular. Young birds before fledging are called goslings. A group of geese on the ground is called a gaggle; when geese fly in formation they are called a wedge or a skein (see also list of collective nouns for birds).
True geese
There are three living genera of true geese: Anser, grey geese, including the domesticated goose and the Swan Goose; Chen, white geese (often included in Anser); and Branta, black geese, such as the Canada goose.
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.
Other birds called "geese"
Greylag Goose (Anser Anser) at Spokane River, Washington, USA
Cape Barren Goose
There are a number of mainly southern hemisphere birds called "geese", most of which belong to the shelduck subfamily Tadorninae.
These are:
Orinoco Goose, Neochen jubata
Egyptian Goose, Alopochen aegyptiacus
The South American sheldgeese, genus Chloephaga
The prehistoric Madagascar Sheldgoose, Centrornis majori, the "Woodard"
The Blue-winged Goose, Cyanochen cyanopterus belongs either to these, or to lineage closer to ducks.
The Spur-winged Goose, Plectropterus gambensis, is most closely related to the shelducks, but distinct enough to warrant its own subfamily, the Plectropterinae.
The three species of small waterfowl in the genus Nettapus are named "pygmy geese", e.g. the Cotton Pygmy Goose (N. javanica). They seem to represent an ancient lineage like the Cape Barren Goose and the Spur-winged Goose.
A genus of prehistorically extinct seaducks, Chendytes, is sometimes called "diving-geese" due to their large size.
The unusual Magpie Goose is in a family of its own, the Anseranatidae.
The Northern Gannet, a seabird, is also known as the "Solan Goose" although it is a bird unrelated to the true geese, or any other Anseriformes for that matter.
