Lesser black-backed gull

The lesser black-backed gull (Larus fuscus) is a big seabird that nests along Europe’s Atlantic and Arctic coasts. It migrates, spending winters from the British Isles down to West Africa, but its numbers have surged in North America, particularly on the east coast. What was once only a winter visitor now shows up in huge flocks some winters, and birds can be seen there all year. Still, there is serious worry about population drops across much of its range. The species is on the UK Amber List because the United Kingdom holds 40 percent of the global population, and over half of those birds are packed into fewer than ten breeding sites.

Carl Linnaeus first described this gull in his 1758 *Systema Naturae*, and it keeps its original name, *Larus fuscus*. The Latin *Larus* likely meant a gull or big seabird, while *fuscus* meant black or brown.

Five subspecies are accepted.

The lesser black-backed gull is smaller than the European herring gull. The classification of the herring gull and lesser black-backed gull group is messy—experts recognize anywhere from two to eight species. This group forms a ring species around the Northern Hemisphere. Nearby forms look pretty similar, but by the time you go full circle, the end members—herring gull and lesser black-backed gull—are clearly different species. The bird measures 51–64 cm long, with a wingspan of 124–150 cm, and weighs 452–1,100 g. The nominate race is a bit smaller than the other two subspecies. Males average 824 g, slightly heavier than females at 708 g. Wing chord is 38–45 cm, bill 4.2–5.8 cm, and tarsus 5.2–6.9 cm. A similar species is the great black-backed gull, but the lesser is much smaller, with a slimmer build, yellow legs instead of pinkish, and smaller white “mirrors” on the wingtips. Adults have black or dark grey wings and back, depending on the race. The bill is yellow with a red spot that chicks peck at to trigger feeding. In winter, the head is greyer, unlike the great black-backed gull’s. Adult moult starts between May and August and may not finish until November; a partial prebreeding moult happens from January to April. Young birds have scaly black-brown upperparts and a neat wing pattern. They take four years to mature. The easiest way to tell them from juvenile herring gulls is the more solidly dark, unbarred tertial feathers.