General

Great Black-backed Gull: The world's largest gull. White head, black upperparts, white underparts, large yellow bill with red spot, variably pale-eyed with red orbital ring, pink legs.

Range and Habitat

Great Black-backed Gull: Northeast North America (and northwestern Europe). Atlantic Coast (expanding southward), Maritimes, Saint Lawrence River and Great Lakes except Lake Superior.

Breeding and Nesting

Great Black-backed Gull: Monogamous; colonial but occasionally solitary. Nest of grasses, seaweed, moss, feathers, debris, and sticks built by both sexes on ground atop small pile of grasses or seaweed, often sheltered in ridges of cliff; two to three buff, olive, or brown eggs with brown spots. Incubation ranges from 26 to 29 days and is carried out by both sexes. Chicks are fed by both parents.

Foraging and Feeding

Great Black-backed Gull: Pugnacious, predatory and opportunistic. Omnivorous. Eats carrion, fish, refuse, eggs and young of other birds, mollusks, crustaceans, rodents, berries, and insects. Steals food from other birds and scavenges on beaches. May take prey as large as other gulls, cormorants, and rabbits.

Vocalization

Great Black-backed Gull: Deep calls "gowl," or "gawp." Laughlike "hah-hah-hah," or "owk-owk." On breeding grounds low screeching "keeeeeeee-aaaahh."

Similar Species

Great Black-backed Gull: Herring Gull smaller, with much lighter gray wings.