Guide to North American Birds

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Breeding adult. Photo: Mark Eden/Audubon Photography Awards

Great Black-backed Gull

Larus marinus

Our largest gull. Primarily a bird of the Atlantic Coast, seldom seen inland except around the Great Lakes. Because of its large size and omnivorous feeding habits, the Great Black-back can be a significant predator on other species of birds during the nesting season. It has benefitted from certain human activities (such as the establishment of garbage dumps) and has expanded its range southward along the Atlantic seaboard in recent decades.

Conservation status	Has been increasing its population in North America at least since the 1930s, with the breeding range steadily expanding southward along the Atlantic Coast and inland to some areas of the Great Lakes.
Family	Gulls and Terns
Habitat	Mainly coastal waters, estuaries; a few on large lakes. Close to coast at most seasons, but will forage far offshore in winter over the continental shelf. Some regularly move inland along St. Lawrence River to Great Lakes, rarely other fresh waters. Nests mostly on islands, tops of sea cliffs, sometimes on mainland beaches and marsh edges.

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Feeding Behavior

Opportunistic. Forages on foot, while flying, or while swimming. May steal food from other birds. May break open hard-shelled mollusks and eggs by flying high and dropping them on rocks. Often scavenges on refuse around fishing boats, docks, garbage dumps.

Eggs

2-3, sometimes 1-5. Olive to buff with brown blotches. Incubation is by both sexes, 27-28 days. Young: Both parents care for and feed young. Downy young may wander from nest after a few days, but remain in general area. Young are capable of flight at 7-8 weeks after hatching, become independent soon thereafter.

Young

Both parents care for and feed young. Downy young may wander from nest after a few days, but remain in general area. Young are capable of flight at 7-8 weeks after hatching, become independent soon thereafter.

Diet

Omnivorous. Diet includes carrion, fish, mollusks, crustaceans, marine worms, insects, rodents, berries, and the adults, young, and eggs of other birds.

Nesting

Usually first breeds at age of 4-5 years. Generally nests in colonies, often mixed with Herring Gulls or other birds; sometimes nests in isolated pairs. Nest site is on ground, often on top of or beside a rocky outcropping. Nest (built by both sexes) is mound of grass, seaweed, moss, debris, with shallow depression in center.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Present all year in most parts of breeding range, but withdraws in winter from coast of Labrador, and a few move south as far as Florida. Numbers in southeast and on Great Lakes increase in winter. Very rare on Gulf Coast and in most inland areas.

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Migration

All Seasons - Common
All Seasons - Uncommon
Breeding - Common
Breeding - Uncommon
Winter - Common
Winter - Uncommon
Migration - Common
Migration - Uncommon

Songs and Calls

Similar to that of Herring Gull, but deeper and more guttural, a deep keeow.

Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Great Black-backed Gull

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You

Climate threats facing the Great Black-backed Gull

Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.