The Gyrfalcon (pron.: /ˈdʒɜrfɔːlkən/ or /ˈdʒɜrfælkən/), also spelled gerfalcon, — Falco rusticolus — is the largest of the falcon species. The Gyrfalcon breeds on Arctic coasts and the islands of 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. The Gyrfalcon is dispersed throughout much of the Northern Hemisphere, with populations in Northern America, Greenland, and Northern Europe. Its plumage varies with location, with birds being coloured from all-white to dark brown. For centuries, gyrfalcon has been a precious hunting bird, highly valued among the Vikings. It is the national symbol of Iceland.