The European herring gull (Larus argentatus) is a large gull, up to 66 cm (26 in) long. It breeds throughout the northern and western coasts of Europe. Some European herring gulls, especially those resident in colder areas, migrate further south in winter, but many are permanent residents, such as in Ireland, Britain, Iceland, or on the North Sea shores. They have a varied diet, including fish, crustaceans, as well as some plants, and are also scavengers, consuming carrion and food left by or stolen from humans.
The male European herring gull is 60–67 cm (24–26 in) long and weighs 1,050–1,525 g (2.315–3.362 lb), while the female is 55–62 cm (22–24 in) and weighs 710–1,100 g (1.57–2.43 lb). The wingspan can range from 125 to 155 cm (49 to 61 in). Among standard measurements, the wing chord is 38 to 48 cm (15 to 19 in), the bill is 4.4 to 6.5 cm (1.7 to 2.6 in) and the tarsus is 5.3 to 7.5 cm (2.1 to 3.0 in).[8] Adults in breeding plumage have a light grey back and upper wings and white head and underparts. The wingtips are black with white spots known as "mirrors". The bill is yellow with a red spot and a ring of bare yellow skin is seen around the pale eye. The legs are normally pink at all ages, but can be yellowish, particularly in the Baltic population, which was formerly regarded as a separate subspecies "L. a. omissus". Non-breeding adults have brown streaks on their heads and necks. Male and female plumage are identical at all stages of development, but adult males are often larger.
Juvenile and first-winter birds are mainly brown with darker streaks and have a dark bill and eyes. Second-winter birds have a whiter head and underparts with less streaking and the back is grey. Third-winter individuals are similar to adults, but retain some of the features of immature birds such as brown feathers in the wings and dark markings on the bill. The European herring gull attains adult plumage and reaches sexual maturity at an average age of four years.
