Justification This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Family/Sub-family Gaviidae

Species name author (Gray, 1859)

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Cramp and Simmons (1977-1994), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

17,000 - 26,000

unset

4,030,000 km²

No

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: Behaviour This species is fully migratory¹. It breeds from early-June (largely depending upon the timing of the spring thaw) in solitary pairs, after which it travels southwards and towards the coast¹ to its wintering grounds where it is present between October and May³. Outside of the breeding season the species occurs singly, in pairs or in small groups³. Habitat Breeding The species may breed on low-lying Arctic coasts and estuaries but is more common on freshwater pools, lakes or rivers in the Arctic tundra¹, showing a preference for deep⁶, clear lakes with stony or sandy substrates² where water levels do not fluctuate⁵. Optimum habitats include lakes where the water does not completely freeze, which have dependable supplies of fish and which have highly convoluted shorelines and aquatic vegetation providing habitats for fish and sites for nesting and brood rearing⁶. The species generally avoids forested areas¹ but may fly long distances to feed away from breeding waters³. Non-breeding Outside of the breeding season the species inhabits inshore waters¹, fjords with muddy substrates⁴ and inlets³ along sheltered coasts¹, generally avoiding ice-covered waters¹. Diet Its diet is little known but may consist predominantly of fish (e.g. Cottidae, Microgadus proximus and Gadus morhua) as well as crustaceans, molluscs and marine annelids¹. Breeding site The nest is a small depression² in a mound of plant matter or turf¹ constructed on dry land^{1, 2} 1 m away⁵ from the edge of water^{1, 2}, usually on the shores of lakes with deep⁶, clear water and stony or sandy substrates² in sites providing good visibility over the surrounding land and water⁵.

Threats The species is vulnerable to coastal oil spills in both its breeding and wintering ranges¹, and may be threatened by oil development activities on its Alaskan breeding grounds (if these lead to fluctuations in water level)⁵. Wintering individuals are also potentially threatened by heavy metal pollution and by drowning in fishing nets (particularly in the north Pacific)¹.

References 1. del Hoyo et al. (1992). 2. Flint et al. (1984). 3. Snow and Perrins (1998). 4. Byrkjedal, et al. (2000). 5. North and Ryan (1989). 6. Earnst et al. (2006).

Further web sources of information

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Text account compilers Stuart Butchart (BirdLife International), Jonathan Ekstrom (BirdLife International), Lucy Malpas (BirdLife International)

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

Recommended citation BirdLife International (2009) Species factsheet: Gavia adamsii. 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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