The Great Black-backed Gull (Larus marinus) is the world's largest gull, a powerfully built bird 64–78 cm long with a wingspan of 150–170 cm and a weight of 1.2–2.0 kg. A coal-black back and upperwings contrast sharply with a snow-white body and head, and the massive yellow bill carries a red spot on the lower mandible; the legs are pale pink. Juveniles are mottled brown and take about four years to acquire full adult plumage.
Its call is a deep, harsh, guttural "aow-aow", noticeably darker and more powerful than the Herring Gull's laughing call, often heard from breeding cliffs and around harbours. The species breeds along Sweden's coasts on both the Baltic and the west coast, typically singly or in loose groups rather than dense colonies; egg-laying runs from early April to mid-May, with 2–3 eggs incubated by both parents for 26–28 days and chicks fledging after 45–60 days. An opportunistic omnivore, it takes fish, carrion and refuse, steals food from other birds, and is one of the few gulls that regularly hunts and kills smaller seabirds along with their eggs and chicks, making it a significant predator at seabird colonies. Although still classed as globally Least Concern, the Swedish breeding population fell from around 15,000 pairs in 2008 to roughly 8,000 by 2018, and the species was uplisted to Endangered (EN) on Sweden's 2025 national red list following this steep and sustained decline.
Read about this species in Swedish →