Greylag goose the western greylag goose, breeds in Iceland and north and central Europe; "A. a. rubrirostris", the eastern greylag goose, breeds in Romania, Turkey and Russia eastwards to northeastern China. The two subspecies intergrade where their ranges meet. The greylag goose sometimes hybridises with other species of goose including the barnacle goose ("Branta leucopsis") and the Canada goose ("Branta canadensis"), and occasionally with the mute swan ("Cygnus olor"). The greylag goose was one of the first animals to be domesticated; this happened at least 3000 years ago in Ancient Egypt, the domestic breed being known as "A. a. domesticus". As the
Goose 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". The three living genera of true geese are: "Anser", grey geese, including the greylag goose, and domestic geese; "Chen", white geese (often included in "Anser"); 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,