Not all the geese in the flocks wintering here are Snow Geese. Maybe 10-20% are actually Ross’s Geese.
This goose breeds in northern Canada, mainly in the Queen Maud Gulf Migratory Bird Sanctuary, and winters much further south in the continent in the southern United States and occasionally northern Mexico.
The plumage of this species is white except for black wing tips. It is similar in appearance to a white-phase snow goose, but about 40% smaller. Other differences from the snow goose are that the bill is smaller in proportion to its body and lacks "black lips". The dark phase is extremely rare.
Ross's goose is a rare vagrant to Western Europe, but it is commonly kept in wildfowl collections, so the true frequency of wild birds is hard to ascertain. Escaped or feral specimens are encountered frequently, usually in the company of other feral geese such as Canada, greylag, and barnacle geese. However, individuals or small groups that seemed to be of natural origin have turned up in the Netherlands and Britain.
This species is named in honor of Bernard R. Ross, a Hudson's Bay Company factor at Fort Resolution in Canada's Northwest Territories.Wikipedia