Brünnich's Guillemot
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| Brünnich's Guillemot / Thick-billed Murre | ||||||||||||||||||||||||||
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 Adults in breeding plumage
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| Uria lomvia (Linnaeus, 1758) |
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Alca lomvia Linnaeus, 1758 |
The Thick-billed Murre or Brünnich's Guillemot (Uria lomvia) is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies Uria lomvia arra is also called Pallas' Murre after its describer.
It breeds on coasts and islands in the High Arctic of Europe, Asia and North America, where it is one of the most numerous bird species.
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[edit] Description
At 40-44 cm in length, with a 64-75 cm wingspan, this species is only marginally larger than the closely related Common Guillemot (or Common Murre, U. aalge). Nonetheless, since the extinction of the Great Auk in the mid-19th century, it is the largest living member of the Alcidae[1].
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. This species produces a variety of harsh cackling calls at the breeding colonies, but is silent at sea.
They differ from the Common Murre in their thicker bill with white gape stripe and their darker back; the "bridled" morph is unknown in U. lomvia - a murre has either a white eye-stripe, or a white bill-stripe, or neither, but never both; it may be that this is character displacement, enabling individual birds to recognize conspecifics at a distance in the densely-packed breeding colonies as the bridled morph is most common by far in North Atlantic colonies where both species of guillemots breed. In winter, there is less white on the Thick-billed Murre's face. They look shorter than the Common Murre in flight.
[edit] Ecology
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. They are rare in temperate waters.
The Thick-billed Murre's flight is strong and direct, and they have fast wing beats due to the short wings. These birds forage for food like other auks, by using their wings to swim underwater. They are accomplished divers, reaching depths of up to 150 m and diving for up to four minutes at a time; usually however birds make either shallow short dives or dive down to 21-40 m for longer periods[2]. Adults mainly eat invertebrates and a few fish and provision their chicks with fish, squid, some crustaceans and other small invertebrates[3]. They carry these prey items to their chicks, one at a time, in their bill. Birds will make long trips to get to favorite feeding grounds; while they usually forage several dozen km from their nest sites, they often travel more than 100 km to fish[4].[1]
The diving depths and durations regularly achieved by these birds indicate that they, and similar auks, have some - as yet unknown - mechanism to avoid diving sickness and lung collapse when surfacing.[2]
[edit] As a vagrant
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 a auk colony in summer 1989. The 1989 and 2005 birds were both found by the same observer, Martin Heubeck.
The species has been recorded once in Ireland[citation needed], and has also been recorded in The Netherlands. In the western Atlantic, they may range as far as South Carolina, and in the Pacific to California.[1] Before 1950 large numbers appeared on the North American Great Lakes in early winter, passing up the St. Lawrence River from the East coast. Such irruptions have not been seen since 1952 [5].
[edit] Status and conservation
Intensive egg harvesting and hunting of adult birds are important threats in Newfoundland and Greenland. In the Barent Sea it has declined locally due to influences associated with polar stations in Russia. Fisheries may be a threat[3], but due to their ability to utilise alternative food sources the effect of over-fishing is not as severe as on the Common Murre. Pollution from oil and gas exploitation exerts a serious threat on the other hand; the rpesent species is among 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.[6]
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[7]. Dates for egg-laying advanced with the earlier disappearance of ice. The number of chicks produced is lower in warmer years. In extremely warm years, mosquitos and heat kill some male breeders.[8]
[edit] Footnotes
[edit] References
- Bakken, Vidar & Pokrovskaya Irina V. (2000): Brünnich's Guillemot. In: Anker-Nilssen, T.; Bakken, Vidar; Strom, H.; Golovkin, A.N.; Bianki, V.V. & Tatarinkova, I.P. (eds.): The status of marine birds breeding in the Barents sea region. Norwegian Polar Institute Report Series 113: 119-124
- 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
- Croll, Donald A.; Gaston, Anthony J.; Burger, Alan E. & Konnoff, Daniel (1992): Foraging behavior and physiological adaptation for diving in Thick-billed Murres. Ecology 73(1): 344-356. doi:10.2307/1938746 (HTML abstract, first page image)
- Gaston, Anthony J. (1988): The mystery of the murres: Thick-billed murres, Uria lomvia , in the Great Lakes region, 1890-1986. Canadian Field-naturalist 102: 705-711.
- Gaston, Anthony J.; Hipfner, J. Mark & Campbell, D. (2003): Heat and mosquitoes cause breeding failures and adult mortality in an Arctic-nesting seabird. Ibis 144: 185-191.
- Gaston, Anthony J.; Woo, Kerry & Hipfner, J. Mark (2003): Trends in Forage Fish Populations in Northern Hudson Bay since 1981, as Determined from the Diet of Nestling Thick-Billed Murres Uria lomvia [English with French abstract]. Arctic 56(3): 227–233. PDF fulltext
- Gaston, Anthony J.; Gilchrist, H.G. & Hipfner, J. Mark (2005): Climate change, ice conditions and reproduction in an Arctic nesting marine bird: Brunnich's guillemot (Uria lomvia L.). Journal of Animal Ecology 74(5): 832–841. doi:10.1111/j.1365-2656.2005.00982.x (HTML abstract)
- Harrison, Peter (1988): Seabirds (2nd ed.). Christopher Helm, London. ISBN 0-7470-1410-8
- Lilliendahl, K.; Solmundsson, J.; Gudmundsson, G.A. & Taylor, L. (2003): Can surveillance radar be used to monitor the foraging distribution of colonially breeding alcids? [English with Spanish abstract] Condor 105(1): 145–150. DOI: 10.1650/0010-5422(2003)105[145:CSRBUT]2.0.CO;2 HTML abstract
- National Geographic Society (2002): Field Guide to the Birds of North America. National Geographic, Washington DC. ISBN 0-792-26877-6
- Nettleship, David N. (1996): 3. Thick-billed Murre. In: del Hoyo, Josep; Elliott, Andrew & Sargatal, Jordi (eds.) (1996), Handbook of Birds of the World (Volume 3: Hoatzin to Auks): 710-711, plate 59. Lynx Edicions, Barcelona. ISBN 84-87334-20-2
- Parmesan, Camille (2006): Ecological and Evolutionary Responses to Recent Climate Change. Annu. Rev. Evol. Ecol. Syst. 37: 637–669. doi:10.1146/annurev.ecolsys.37.091305.110100 PDF fulltext
- Sibley, David Allen (2000): The Sibley Guide to Birds. Alfred A. Knopf, New York. ISBN 0-679-45122-6
[edit] External links
- Review of discussion about recent hunting regulations on Greenland. In Danish and English.
