Black-headed Gull

The black-headed gull is a small gull, 34–39 centimetres long with a wingspan of 100–110 centimetres, weighing 166–400 grams; males average heavier than females, with much overlap. In flight, the white leading edge of the outer wing, combined with the dark underside of the inner primaries, is a good field mark and separates it from the closely related Bonaparte's gull. Some authorities recognise a slightly larger, longer-winged eastern subspecies, sibiricus, in far eastern Siberia, though the variation is probably clinal. (Wikipedia, general species account)

Black-headed gulls breed across the Palearctic over much of Europe and northern Asia, from Iceland and Ireland east to Japan and eastern China. The species is abundant, with a global population of two to three million pairs, most numerous in Europe. Most of the population is migratory and winters further south, though many remain in the milder areas of northwestern Europe. The range has been slowly expanding westwards, with Iceland first colonised in 1911 and Greenland in 1969. (Wikipedia, general species account)