Larus argentatus - Herring Gull
Larus cachinnans - Yellow-legged Gull
Feather characters. Barbules are from short until medium length (0.43-1.15 mm). Pigmentation is slight or absent, although occasionally some pigment may be seen in basal-most nodes. Both vase-shaped and slightly thickened nodes are present. Nodes are equally distributed along the entire length of barbules (12-24 per mm). Proximal nodes are vase-shaped, they abruptly decrease in size into slightly thickened nodes distally. Villi are absent and internodes are straight. Minute prongs are present on distal end of barbules and on both sides of the pennulum.
Today Larus argentatus and Larus cachinnans are considered as two separate species. But since Larus cachinnans occurs also in the area we cover, it is also included.
Field characters. Size 55-66 cm. Weight: male 1226 g (755-1495), female 1044 g (717-1385) (Dunning, 1993). Highly variable in size, with male considerably larger than female. May be confused with Common Gull, but is much larger, with heavier bill (with red spot on gonys) and flesh-pink legs. Black wing-tips distinguish this species and Common Gull from Glaucous Gull (Larus hyperboreus, not included in BRIS) and Iceland Gull (Larus glaucoides, not included in BRIS). Mantle and upperwing are pale bluish grey; wing-tips black with white spots; rest of plumage white. Winter plumage similar, but with some greyish streaks on head, neck and upper breast. Juvenile is difficult to distinguish from juvenile Lesser Black-backed Gull; in flight, somewhat more uniform in appearance, without obvious contrast between subterminal band on tail and surrounding parts and with contrast between dark outer and lighter inner primaries (all primaries dark in juvenile Lesser Black-backed Gull). A common gull, which is markedly more aggressive than its congeners.
Voice. A repeated, harsh "kyow" is its most common call; a wide variety of other calls is also heard.
Distribution. A common breeding bird; locally very common. Northernmost populations are migratory, but others are resident. Map: see MapIt.
Habitat. Breeds at or near coast in colonies, on coastal cliffs, islands and beaches, and in recent years, also on buildings. Outside breeding season, habitat choice similar, but can also be found inland on freshly ploughed fields and refuse dumps.
Food. Will eat any kind of animal matter, be it alive or dead; also some vegetable matter and human refuse.