辨識
Very large, pale gull. Adults are mostly white with a very pale gray back; note pure white wingtips. Immatures are white or pale tan with light brown markings; also look for the distinctive pink bill with sharply demarcated black tip. Most similar to Iceland Gull but larger, larger-billed, and usually even paler; Iceland typically shows more dark markings on wingtips. Also note shorter wingtips on Glaucous that do not extend far past tip of tail. Breeds in the High Arctic; winters farther south in a variety of habitats, rarely far from a large body of water. Often seen in small numbers mixed with flocks of other large gulls. Hybridizes with Glaucous-winged Gull and Herring Gull in parts of range; hybrids can show any mix of intermediate traits and are sometimes best left unidentified.