Larus marinus - Great Black-backed Gull
Feather characters. Barbules are from short until medium length (0.9-1.5 mm). Barbules are divided into pigmented nodes and unpigmented internodes. Pigmentation may vary among different body feathers, occasionally pigmentation is slight or absent. Vase-shaped nodes are located on proximal end of barbules (12-16 per mm). Over a short distance these nodes abruptly decrease in size. Distally nodal structures are too small to qualify as nodes. Villi are absent and internodes are straight. Minute prongs may be present along the entire length of barbules, on both sides of the pennulum. These prongs are unequally distributed, and many nodal structures without prongs may be found.
Field characters. Size 65-77 cm. Weight: male 1829 g (1380-2272), female 1488 g (1033-2085) (Dunning, 1993). One of the largest gulls; can be distinguished from Lesser Black-backed Gull by its larger size, white-pinkish legs, much stouter bill, and darker colour of upperparts. Mantle and wing slate-black; other parts white. Bill long, heavy and yellow with red spot on gonys. Winter plumage is similar, but with head and rear of neck finely streaked with brown. Juvenile with whitish face, throat and upper chest; rear head, neck and underparts boldly flecked with dusky brown. Mantle and wing-coverts dark brown with creamy white fringes, thus giving diagnostic chequered appearance; tips of primaries brown-black. Bill black, legs pale flesh. In flight, diffuse brown subterminal band on tail and more uniformly coloured inner wing prevent confusion with Herring or Lesser Black-backed Gull.
Voice. Although generally silent, birds may be noisy in groups. Voice reminiscent of Herring or Lesser Black-backed Gull's, but hoarser and deeper. When disturbed, a deep, barking "awwk" or a guttural "uk-uk-uk" are commonly heard.
Distribution. A common breeding bird in temperate parts of the area; increasing in number. Northern populations leave breeding grounds in winter, others are resident. Map: see MapIt.
Habitat. Nests on islands, cliff-ledges, and flat beaches; in undisturbed areas, also inland, on islets in freshwater lakes and rivers, and moors. Outside breeding season often found far from land at sea, on sandy beaches, rocky coasts and estuaries.
Food. Basically omnivorous, although animal matter predominates. A fierce predator, catching birds up to size of Puffin (Fratercula arctica, not included in BRIS) in the air, and occasionally kills weak lambs. Other kinds of food include fish, invertebrates, berries, and human refuse.