The snow goose ("Chen caerulescens" or "Anser caerulescens"), also known as the blue goose, is a North American species of goose. Its name comes from its white feathers. Some authorities place this species in the "Chen" genus. Other authorities place these species in the "gray goose" genus "Anser". In addition to a white phase they also have a blue phase. In the white phase they are all-white except for their primary feathers which are black. In the blue phase the head and upper neck remain white.