White-winged silvery Gull

A pale northern gull, about the size of Herring Gull but more graceful and maneuverable in flight. Despite its name, it occurs in Iceland only during the winter. The typical white-winged form nests only in Greenland, while the "Kumlien's" form, with gray in the wingtips, nests in northeastern Canada and winters mostly in eastern Canada and the northeastern United States. The "Thayer's" form, considered a separate species until recently, nests in far northern Canada and winters mainly along the Pacific Coast. The latter two forms seem to intergrade where their nesting ranges come in contact in the Baffin Island region of Arctic Canada.