Thick-billed Murre (Uria lomvia)

Taxonomy

Four subspecies recognized:
U. l. lomvia
U. l. eleonorae
U. l. heckeri
U. l. arra

Also known as Brunnich's Guillemot
 

Identification

Potential confusion with Common Murre, especially birds in transitional plumages.
In all plumages, Thick-billed Murres are blackish-brown, lacking the warm chocolate tone of Common Murre. In alternate plumage, the white of the breast cuts into the black throat as an inverted 'V'. In basic plumage, the dark of the crown extends further down the sides of the head so that the line of demarkation between the black and white runs straight back from the bill. Common Murre's have a series of dark stripes along the flanks. These are absent in Thick-billed Murre, although beware of false stripes caused by the white flank feathers riding up over the dark wings.

At close range, bill shape is paticularly useful. In adult Thick-billed Murres, the bill is deeper and also shorter than that of Common Murre. The culmen shows an even curve throughout its length. The white tomium stripe is less obvious in basic plumage but is often still visible. Beware however, as occasional Common Murres show a hint of a stripe.


Like spectators in a sports arena, Thick-billed Murres (Uria lomvia) and Black-legged Kittiwakes (Rissa tridactyla) crowded the steeper cliffs on Chagulak in the western Aleutians, June 1997. Photograph copyright of Angus Wilson©.

 

Where and When

Almost circumpolar in the Arctic and near Arctic. In the Atlantic, breeds on a number of islands in the Canadian arctic reaching as far south as Newfoundland. Also breeds in Greenland, Iceland, northern Norway, Spitzbergen, Novaya Zemlya, northern Russia, northern Siberia to the Bering Sea. In the Pacific breeds from British Columbia through the Aleutians and coastal Alaska to Kamchatka.

In winter, disperses out to sea but remains in relatively high latitudes (for example, remains well north of Scotland). Remains an extremely rare vagrant to the British Isles (32 records as of 1995), many records refering to beach-washed birds. This seems remarkable given the fact that at least 2 million pairs breed in Iceland. In the Pacific is only casual to central California (Monterey Bay) or Japan.

Photographs on the web

Series of very instructive images showing four individuals at slightly different stages of transition from basic to alternate plumage. Photographed by Don Crockett in Massachusetts in late February.

Detail of head of alternate adult and another shot of an adult yawning!. Photos by Arthur Morris and hosted by Don Crockett/The Virtual Birder.
 

Literature

Benvenuti, S., et al. (1998) Foraging flights of breeding Thick-billed Murres (Uria lomvia) as revealed by bird-borne direction recorders. Auk 115: 57-66.



Copyright © 2002 All rights reserved. Angus Wilson

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