Great Black-backed Gull

The Great Black-backed Gull (Larus marinus), often referred to as the "king of the Atlantic waterfront," is the largest member of the gull family. This imposing bird is characterized by its white head, neck, and underparts, contrasting with its dark grey wings and back. The pink legs and yellow bill, with a hint of orange or red near the tip, complete its striking appearance.

Identification Tips

Adults are easily identified by their sheer size, dark grey to blackish upper-wings, and white "mirrors" at the wing tips. The bill is robust and yellow, with a red spot near the tip of the lower mandible. Juveniles display a mottled black-brown pattern with a white tail featuring dark bars and spots at the base. They undergo a gradual transition to adult plumage over four years.

Habitat

The Great Black-backed Gull frequents a variety of coastal environments, including rocky shores, sandy beaches, and estuaries. It is also found inland near lakes, ponds, rivers, and wet fields. This species is adaptable and can be seen at refuse dumps and dredge spoils, especially in New Jersey.

Distribution

Breeding along the coasts and islands of the North Atlantic, this gull's range extends from the northwest of Russia through Scandinavia, the Baltic Sea coasts, to northwestern France, the UK, and Ireland. Across the Atlantic, it is found in Iceland, the Faroe Islands, southern Greenland, and the Atlantic coasts of Canada and the United States. Some populations migrate southward in winter, reaching as far as the Caribbean and northern South America.

Behaviour

The Great Black-backed Gull is sedentary, with some individuals moving south or inland during winter. It is a dominant and aggressive bird, often seen scavenging or kleptoparasitizing other birds. This gull is also known for its predatory habits, hunting a wide range of prey from fish to other seabirds.

Song & Calls

Its call is a deep "laughing" cry, kaa-ga-ga, with the first note sometimes drawn out. The voice is notably deeper than that of most other gull species.

Breeding

Breeding occurs in small colonies or singly, often on islands or other predator-inaccessible locations. Nests are made on the ground and lined with grass, seaweed, or other materials. The typical clutch consists of three greenish-brown eggs with dark markings. Both parents share incubation duties for about 28 days and care for the chicks, which fledge at around 50 days old.

Similar Species

The Lesser Black-backed Gull (L. fuscus) is smaller with yellowish legs and a lighter mantle. Other dark-backed gulls, such as the Slaty-backed Gull (L. schistisagus) and the Kelp Gull (L. dominicanus), are similar but inhabit different ranges.

Diet and Feeding

An opportunistic feeder and apex predator, the Great Black-backed Gull consumes a wide variety of food, including fish, crustaceans, mollusks, insects, small birds, and carrion. It is known to scavenge at refuse dumps and exploit human-provided resources.

Conservation Status

The species is currently listed as Least Concern by the IUCN. While historically exploited for its feathers, the Great Black-backed Gull has adapted well to human presence and urban environments, leading to an increase in numbers. However, it faces threats from toxic pollutants and human disturbance during breeding.