© Copyright: Images: Jari Peltomäki, Jouko Lehmuskallio, M., W. & F. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland), Pohjolan linnut värikuvin. Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Mew Gull (North American subspecies)
- Family: Gulls – Laridae
- Appearance: One of Finland’s most common gulls. Resembles the Herring Gull, but smaller and has a thinner bill and more rounded head profile.
- Size: Length: 40–46 cm, wingspan 99–108 cm, weight 315–580 g.
- Nest: Carefully made of dry material (grass, twigs, moss). Nests on small rocky islands located fairly near shoreline. Also nests in higher sites on top of large boulders, and sometimes on roofs or in trees.
- Breeding: 2–4 eggs laid from late April, incubated by both parents for 24–28 days. Fledglings learn to fly within 29–33 days.
- Distribution: Finland’s most numerous gull species alongside the Black-headed Gull. Common breeder around all kinds of marine and inland waters. Finnish population estimated at 60,000–80,000 pairs.
- Migration: Winters in Western and SW Europe, especially in Denmark and other countries around the North Sea. May leave Finland between July and November, returning in March–April. Some birds also winter in Finland.
- Diet: Omnivorous, but particularly prefers small fish and invertebrates.
- Calls: A shrill, lengthened “glii-oo”, warning call a harsh “kek-kek-kek”, courtship call “kaya-kaya-kaya-kaya-kaya”.
Common Gulls have white underparts, bluish grey backs and wings, with black wingtips (white spots visible on the very end of the wingtip feathers). Juveniles have mainly dull pale brown upper parts with greyish edges to their feathers, giving them a scaly appearance. They get their adult blue-grey wing colouring only in their second winter plumage, when their primary wing feathers and the front parts of their wing coverts still have carried darker patterning.
Adults have greenish yellow legs and beaks, while juveniles’ legs are greyish or pinkish and their beaks are ivory-coloured with black tips. The beaks of immature birds in their second winter are grey with a yellow tip and a dark band behind the tip. Common Gulls’ irises may be greyish brown surrounded by a red eye-ring (mature birds) or dark brown with a brownish orange eye ring (juveniles).