Brünnich's Guillemot
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| Uria lomvia (Linnaeus, 1758) |
The Brünnich's Guillemot, or Thick-billed Murre, Uria lomvia, is a bird in the auk family. It breeds on coasts and islands in the high Arctic of Europe, Asia and North America. It is one of the most numerous in the high arctic.
These birds breed in large colonies on coastal cliffs, their single egg being laid directly on a cliff ledge. They move south in winter into northernmost areas of the north Atlantic and Pacific, but only to keep in ice-free waters. The larger size of this species makes it less prone than the Little Auk to be carried further south by late autumn storms, and they are consequently rare in temperate latitudes.
At 40-44 cm in length, with a 64-75 cm wingspan, this species is only marginally larger than the closely related Common Guillemot.
Adult birds are black on the head, neck, back and wings with white underparts. The bill is long and pointed. They have a small rounded black tail. The lower face becomes white in winter. They differ from Common Guillemot in their thicker bill, darker back and white gape stripe. In winter, there is less white on the face.
The Brünnich's Guillemot's flight is strong and direct, and they have fast wing beats due to the short wings. They look shorter than Common Guillemot in flight. These birds forage for food like other auks, by using their wings to swim underwater. They are accomplished divers, reaching depths of over 140 m and diving for over four minutes at a time. Adults mainly eat invertebrates and a few fish. Adults provision their chicks with fish, squid, some crustaceans and other small invertebrates. They carry these prey items to their chicks, one at at time, in their bill.
This species produces a variety of harsh cackling calls at the breeding colonies, but is silent at sea.
This bird is named after the Danish zoologist Morten Thrane Brünnich.
[edit] Threats
Intensive egg harvesting and hunting of adult birds are important threats in Newfoundland and Greenland. In the Barentsee it is now reduced to local influences associated to polar stations in Russia. Fisheries may be a threat, but due to their ability to utilise alternative food sources the effect of over-fishing is not as much as on the common guillemots. Pollution of oil and gas exploitation exerts a serious threat. It's one of the seabirds most sensitive to these influences. Gas condensate and oil deposit can be of great harm. Incidental mortality in fishing gear is also important (Vidar Bakken, Irina V. Pokrovskaya, 2000).
Climate change is also considered to be a threat for this Arctic-breeding species. Populations at the southern edge of their range switched from feeding on ice-associated Arctic cod to warmer-water capelin. Dates for egg-laying advanced with the earlier disappearance of ice. The number of chicks produced is lower in warmer years. In especially warm years, mosquitoes and heat kill many of the male birds.
[edit] Status in Europe south of the breeding range
Brünnich's Guillemot is a rare vagrant in European countries south of the breeding range. In Britain, over 30 individuals have been recorded, but over half of these were tideline corpses. Of those that were seen alive, only three have remained long enough to be seen by large numbers of observers. All three were in Shetland — winter individuals in February 1987 and November/December 2005, and a bird in an auk colony in summer 1989 (the 1989 and 2005 birds were both found by the same observer, Martin Heubeck).
Brünnich's Guillemot has been recorded once in Ireland, and has also been recorded in The Netherlands.
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[edit] References
- BirdLife International (2004). Uria lomvia. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is of least concern
- "National Geographic" Field Guide to the Birds of North America ISBN 0-792-26877-6
- Seabirds, an Identification Guide by Peter Harrison, ISBN 0-7470-8028-8
- Handbook of the Birds of the World Vol 3, Josep del Hoyo editor, ISBN 84-87334-20-2
- "National Audubon Society" The Sibley Guide to Birds, by David Allen Sibley, ISBN 0-679-45122-6
- Scientific discussion about recent hunting regulations on Greenland
- Scientific [1] "Foraging behavior and physiological adaptation for diving in thick-billed murres"
- Scientific [2] "Climate change, ice conditions and reproduction in an Arctic nesting marine bird: Brunnich's guillemot (Uria lomvia L.)"
- Scientific [3] "Trends in Forage Fish Populations in Northern Hudson Bay since 1981, as Determined from the Diet of Nestling Thick-Billed Murres Uria lomvia"
