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The Great Black-backed Gull (Larus marinus), also known as the greater black-backed gull or, informally, as the black-back, is the largest member of the gull family. It breeds on the European and North American coasts and islands of the North Atlantic and is fairly sedentary, though some black-backs move farther south or inland to large lakes or reservoirs. The adult great black-backed gull has a white head, neck and underparts, dark grey wings and back, pink legs and yellow bill.

This is the largest gull in the world, noticeably out sizing a herring gull (Larus argentatus). Only a few other gulls, including Pallas's gull (Ichthyaetus ichthyaetus) and glaucous gull (Larus hyperboreus), come close to matching this species' size. It is 25–31 in long with a 4 ft 11 in–5 ft 7 in wingspan and a body weight of 1.7–5.1 lb). The great black-backed gull is bulky and imposing in appearance with a large, powerful bill.

The adult great black-backed gull is fairly distinctive, as no other very large gull with blackish coloration on its upper-wings generally occurs in the North Atlantic. The legs are pinkish, and the bill is yellow or yellow-pink with some orange or red near tip of lower bill. The adult lesser black-backed gull (L. fuscus) is distinctly smaller, typically weighing about half as much as a great black-back. The lesser black-back has yellowish legs and a mantle that can range from slate-gray to brownish-colored but it is never as dark as the larger species. A few superficially similar dark-backed, fairly large gulls occur in the Pacific ocean or in the tropics, all generally far outside this species' range, such as the kelp gull (L. dominicanus).

The great black-backed gull is found in a variety of coastal habitats, including rocky and sandy coasts and estuaries, as well as inland wetland habitats, such as lakes, ponds, rivers, wet fields and moorland. They are generally found within striking distance of large bodies of water while ranging inland. Today, it is a common fixture at refuse dumps both along coasts and relatively far into land. The species also makes extensive use of dredge spoils, which, in the state of New Jersey, comprise the most prevalent nesting sites for them. It generally breeds in areas free of or largely inaccessible to terrestrial predators, such as vegetated islands, sand dunes, flat-topped stacks, building roofs and sometimes amongst bushes on salt marsh islands.

Unlike most other Larus gulls, they are highly predatory and frequently hunt and kill any prey smaller than themselves, behaving more like a raptor than a typical larid gull. Lacking the razor-sharp talons and curved, tearing beak of a raptor, the great black-backed gull relies on aggression, physical strength and endurance when hunting. When attacking other animals, they usually attack seabird eggs, nestlings or fledgings at the nest, perhaps most numerously terns, but also including smaller gull species as well as eiders, gannets and various alcids. In Newfoundland and Nova Scotia, 10% of the stomach contents of great black-backed gulls was made up of birds, while a further 17% of stomach contents was made up of tern eggs alone.

This is a relatively long-living bird. The maximum recorded age for a wild great black-backed gull is 27.1 years.

Historically, the great black-backed gull was harvested for its feathers, which were used in the hat-making trade, and this species was removed from large parts of its range as a result of this exploitation. Today however, its adaptability to human presence and the use of urban environments as artificial nesting sites has resulted in the great black-backed gull rapidly increasing in number and range. It is now a widespread and abundant species in its range and its numbers have increased to such high levels in some areas that it is often seen as a pest species, especially near airports where it risks collisions with airplanes, and in some coastal areas where it sometimes outcompetes or hunts rarer seabirds, such as Atlantic puffins, possibly resulting in conservationist intervention.

Black-backed Gull

Black-backed Gull 7989

Range Black-backed Gull