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
Cackling goose populations may still be declining, especially of the subspecies "minima" and "leucopareia". Though the taxonomic distinctness of the Komandorski and Kuril Islands populations, which used to winter in Japan, is controversial, it is without doubt that they disappeared around 1929. The genus name "Branta" is a Latinised form of Old Norse "Brandgás", "burnt (black) goose", and the specific epithet "hutchinsii" commemorates English surgeon Thomas Hutchins who was employed by the Hudson's Bay Company. The cackling goose was originally considered to be the same species or a subspecies of the Canada goose, but in July 2004 the American Ornithologists' Union's (AOU)