© Copyright: Images: Jari Peltomäki, Kari Pihlaviita, Jouko Lehmuskallio, M., W. & F. von Wright: Pohjolan linnut värikuvin. Recording: Jan-Erik Bruun. All rights reserved.
Great Black-backed Gull
- Family: Gulls – Laridae
- Appearance: Finland’s largest gull. Beak sturdy, neck thick-set, legs greyish pink. Back and wings black above and mainly white below. Juveniles have many dark and light markings.
- Size: Length 61–74 cm, wingspan 144–166 cm, weight 1.2–1.8 kg.
- Nest: Large, made of grass, moss and other material, in an open site, often on the highest part of a small island, on a rock or on a marshy hummock.
- Breeding: 2–4 eggs laid from late April, incubated by both parents for 26–28 days. Fledglings learn to fly within about 7 weeks.
- Distribution: Breeds on seashores, on islands in large lakes, and in bogs in central regions of Finland. Finnish breeding population estimated at 2,300 pairs.
- Migration: Partially migratory, moves south according to ice conditions. Winters around the southern Baltic and in Western Europe.
- Diet: Omnivorous. Often feeds at rubbish dumps or fishing harbours, and will follow ships at sea. Diet may include fish, fledgling birds, eggs and carrion. May also harass other seabirds to steal food from them.
- Calls: Similar to cries of Herring Gull, but deeper and harsher.
- Endangerment: Vulnerable, unprotected most part of the year. Globally Least concern.
The Great Black-backed Gull is the largest and most sturdily built gull found in Finland. Adults have black wings and backs, with white heads, necks and bellies. Their plumage is very similar to the colouring of the Lesser Black-backed Gull, but they can be distinguished by their broader and blunter wings, the broader white band along the trailing edge of their wings, and their greyish pink legs (Lesser Black-backed Gulls have yellow legs).
Juvenile Great Black-backed Gulls are largely covered in brown and grey patterning, and hard to distinguish from young Herring Gulls. They only gain the first black feathers on their wings and back when they moult after their second winter (January–April). Great Black-backed Gulls’ legs are greyish pink (adults) or purplish brown (juveniles). Their irises may be pale yellow (adults) or dark brown (juveniles). Adults’ bills are yellow with a red spot on the lower mandible. Young birds’ bills are brownish black or yellowish white with a pale tip. Birds in their third winter and summer have dark markings on the middle of their bills. Their bills only gain adult colouring in their fifth year.