Very large, pale gull. Distinguished from most other large gulls by its white wingtips. Adults are almost entirely white with a pale gray back. Young birds are whitish tinged with pale brown markings. Juveniles also have a distinctive pink bill with sharply demarcated black tip. Adults most similar to Iceland Gull but larger, larger-billed, and 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 Arctic; winters farther south in a variety of habitats, rarely far from a large body of water. Often mixes with flocks of other large gulls.