The Slaty-backed Gull (Larus schistisagus), is a large white-headed gull that breeds on the western coast of Alaska but travels widely during nonbreeding seasons. Claims have been made as to its (sometimes occasional) presence throughout North America as well as the eastern coast of Asia. It is similar in appearance to the Western Gull and the Glaucous-winged Gull. Another alternate name is Pacific Gull, though this also applies to a southern hemisphere species, Larus pacificus.

Le goéland à manteau ardoisé (Larus schitisagus) est un oiseau de mer de la des laridés. Au sein de cette famille dont il est l'un des plus grands représentants, il fait partie de la catégorie dite des « grands goélands à tête blanche ».