Justification This poorly known alcid has recently suffered an extremely rapid population decline owing to a variety of threats, qualifying it as Critically Endangered.

Family/Sub-family Alcidae

Species name author (Vigors, 1829)

Taxonomic source(s) AOU checklist (1998 + supplements), Sibley and Monroe (1990, 1993)

Identification 25 cm. Small well-marked alcid. In breeding season upperparts dark grey with irregular fringing of light buff over most feather tracts (except wings and tail). Underparts light buff or off-white, sparse dark streaking on front and sides of head to upper chest. Remaining underparts barred. In winter adult the upperparts and sides of upper breast slate grey, feathers of mantle and rump edged white, underparts (except breast band) white. Similar spp. Distinguished in summer plumage from Marbled B. marmoratus and Long-billed B. perdix by small bill and speckled or streaked plumage. In winter white face extends above eye and has white collar and complete (or nearly complete) breast band. At all times; the outer vanes of the tail feathers are white, making the tail look white as the feathers are spread. Voice Calls 'like that of a small chick' and also a groaning "aaahrr".

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

13,000 - 35,000

decreasing

292,000 km²

No

Range & population Brachyramphus brevirostris has a distribution that is geographically centred on the Bering Sea where it is rare and patchily distributed in both Russia and the USA. In Alaska (where c.70% of the total population occurs²) it is found from just east of Cape Lisburne south to the Aleutian Islands and east to LeConte Bay. In Russia it is limited to the eastern Chukotskiy Peninsula in the Chukchi Sea west to Cape Schmidt and south to Anadyr Gulf, as well as Shelikov Bay in the northern Sea of Okhotsk¹. The Alaskan population was estimated to number 9,000-25,000 birds in 2002². Surveys in much of the Alaskan range indicate that populations have declined by >80-90% during the past 15 years⁵. In Prince William Sound the population declined by 84% between 1989 (6,436 birds) and 2000 (1,033 birds) following a possible longer term decline since 1972 when the population was estimated at 63,000 individuals ^2,6. In the Malaspina Forelands, numbers declined by 38-75% in 1992-2002. In Glacier Bay, density estimates declined by 89.1% in 1991-2000, with c.2,200 birds estimated there in 1999-2000². Total abundance in Icy Bay, Alaska, was estimated to be 1,725-2,372 birds in 2002, suggesting a decline of 59% over a three-year period⁴. There are no trend data from other parts of the species's range, but anecdotal information suggests population declines are occurring in at least some of these other areas. Wintering distribution is largely unknown, although there are records from coastal Kamchatka, the Kuril Islands, Hokkaido (Japan) and the continental shelf of the northern Gulf of Alaska⁹, and birds are present year-round at Kodiak Island (Alaska)¹¹.

Ecology: It lays a single egg on the ground amongst unvegetated scree or on cliff faces, but one recently found nest on Kodiak Island, Alaska was on exposed bedrock¹¹. Breeding was thought to be restricted to sites at or near the tops of mountains in glaciated regions¹, but twelve active nests were recently found on Agattu in the western Aleutians, indicating that the species can nest at high densities in areas far from glaciers¹¹. It generally forages in different water types to the closely related Marbled Murrelet, preferring but not exclusively feeding during the breeding season in turbid waters of glacial origin³. It feeds on fish and macro-zooplankton. The wintering distribution and habitat choice are poorly documented but populations are presumed to winter in ice-free areas to the south of the breeding range¹, or over the open continental shelf offshore of breeding areas.

Threats There have been strong links made between this species's decline and areas of glacial recession (possibly as a result of climate change)^5,6,7. Other threats include habitat degradation and repeated disturbance of birds owing to recreational and commercial tour-boat traffic; mortality in gill-net fisheries (documented in Prince William Sound; anecdotal accounts from elsewhere); mortality from petroleum contamination (7-15% of the Prince William Sound population died as result of the ExxonValdez oil spill); and a change in prey species abundance adversely affecting piscivorous fish¹⁰. Boat traffic in Glacier Bay was found to cause a 30-fold increase in flight behaviour, and nearshore densities of murrelets were temporarily suppressed by vessel passage, although this was not found to result in a persistent loss of foraging habitat¹⁴. In 2008 the US Government auctioned leases to drill for oil and gas in the Chukchi Sea off Alaska, raising the potential prospect of catastrophic oil spills at two major seabird colonies (both with breeding murrelets) if drilling is allowed to commence¹⁵. Near-zero productivity in 1996-1998 for unknown reasons may lead to further future declines⁸. Birds breeding in the western Aleutians have been found to have low reproductive success, with losses during the incubation period primarily due to avian predators locating unattended eggs, and chick mortality during the nestling period largely due to inclement weather¹³.

Conservation measures underway In the USA the species is recognised as a "Species of Conservation Concern" on the Endangered Species Act, and is listed in the Red Book of the USSR⁷. Guidelines have been drawn up in the USA to avoid disturbance of nesting birds. 44 birds were radio-tagged in Icy Bay, Alaska in 2006-2007 which led to the discovery of four active nests.

Conservation measures proposed Monitor population and trends in Alaska and Russia. Assess the impact of gill-net fisheries. Assess the impact of boat traffic on use of foraging areas. Reduce habitat degradation and human disturbance through private sector codes of conduct. Enforce legilsation to reduce the chances of oil-spills and other pollution. Tackle the threat of global climate change through international agreements.

References 1. Day et al. (1999). 2. K. Kuletz in litt. (2002). 3. Day et al. (2003). 4. Kissling (2006). 5. Piatt et al. (undated). 6. Kuletz et al. (2003). 7. Van Pelt (2005) 8. Day and Nigro (2004). 9. Day (2006). 10. Kuletz et al. (2006). 11. Stenhouse et al. (2008). 12. Kissling et al. (2008). 13. Kaler et al. (2008). 14. Agness et al. (2008). 15. BirdLife International (2008).

Further web sources of information

Audubon WatchList

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Ben Lascelles (BirdLife International), Andy Symes (BirdLife International)

Contributors Robert Day (ABR Inc. Environmental Research and Services), Kathy Kuletz (US Fish & Wildlife Service)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Brachyramphus brevirostris. Downloaded from http://www.birdlife.org on 9/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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