© Copyright: Images: Jari Peltomäki, M. & W. von Wright: Svenska fåglar (Kansalliskirjasto, The National Library of Finland). Recording: Jan-Erik Bruun. All rights reserved.
- Name also: Common Guillemot, Common Murre, Thin-billed Murre
- Family: Auks – Alcidae
- Appearance: A true seabird found in the archipelago. Like a Razorbill, but with a thinner, more pointed beak. Head and back dark brown; white underparts.
- Size: Length 38–46 cm (15–18 in), wingspan 61–73 cm (24–28 in), weight 945–1,045 g (38–42 oz).
- Nest: Eggs laid on cliff ledges in most parts of range, but in Finland in shallow depressions on rocky outcrops. No nest material used.
- Breeding: Single egg laid in May, incubated by both parents for 28–49 days. Fledglings fed at nest-sites for 27–30 days, before young birds leave and become independent, even though they are not yet able to fly.
- Distribution: Breeds in colonies, often in large numbers on Atlantic coastal cliffs and island. In the Baltic breeds on rocky islets. Almost became extinct in the Baltic region in the late 19th century, but subsequent recovery aided by protection of their breeding islands (e.g Karlsö, near Gotland in Swedish waters from 1880). In Finland has nested on Aspskär in Pernå since 1956, and today also nests in small numbers in Åland and the Turku Archipelago. Finnish population currently estimated at just 40–130 pairs.
- Migration: Flies south mainly in August, returning in May. Winters in southern waters of the Baltic Sea.
- Diet: Fish including herring, bullhead, sand-eel and cod. Can carry a single fish lengthwise in its bill.
- Calls: Grunts and whimpers, sometimes said to be reminiscent of the angry yelping of a distant pack of dogs.
- Endangerment: Endangered, protected across the whole of Finland, including the Åland Islands. Globally Least concern.
Guillemots are seabirds recognisable by their long, sharp beaks. The most similar relatives are Razorbills, and Brunnich’s guillemot, which is only occasionally seen in Finland. The dark upper parts of Guillemots (head neck and back) are dark brown, and not black as in Razorbills. They have white underparts and their flanks are slightly streaked. Some individuals known as Bridled Guillemots (1% of the Baltic population)have a distinct plumage with white rings round their eyes and a thin white stripe behind each eye.
Guillemots have a single white stripe on each wing behind their secondaries. Their underwings have lengthwise darker and paler streaks, as well as dark axillary patches. In their winter plumage Guillemots’ cheeks and throat turn white, but they keep a blackish cap and a narrow black stripe curving downwards behind each eye. Young Guillemots resemble adults’ in winter plumage, but have less streaking on their flanks and usually a narrow white stripe behind their necks.
Guillemots have black legs with blackish brown webbed feet. During the breeding season males have yellowish brown ankles, and females’ ankles turn more yellowish. Guillemots have black beaks and dark brown irises. They habitually sit like Razorbills with their ankles on the ground.
The Guillemots of the Baltic Sea belong to the race U. a. intermedia, but individuals of the Arctic Ocean race U. a. aalge. are sometimes seen in Finnish Lapland.