The gyrfalcon (Falco rusticolus) (/ˈdʒɜːrfɔːlkən/ or /ˈdʒɜːrfælkən/), also spelled gerfalcon, is a bird of prey, the largest of the falcon species. The abbreviation gyr is also seen in the literature. It breeds on Arctic coasts and tundra, and the islands of northern North America, Europe, and Asia. It is mainly a resident there also, but some gyrfalcons disperse more widely after the breeding season, or in winter. Individual vagrancy can take birds for long distances. Its plumage varies with location, with birds being coloured from all-white to dark brown. These colour variations are called morphs. Like other falcons, it shows sexual dimorphism, with the female much larger than the male. For centuries the gyrfalcon has been a precious hunting bird, highly valued among the Vikings. Typical