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). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not 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 Scolopacidae

Species name author (Pallas, 1764)

Taxonomic source(s) AERC TAC (2003), AOU checklist (1998 + supplements), Christidis and Boles (1994), Christidis and Boles (2008), Cramp and Simmons (1977-1994), Dowsett and Forbes-Watson (1993), SACC (2005 + updates), Sibley and Monroe (1990, 1993), Stotz et al. (1996), Turbott (1990)

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

620,000 - 700,000

unset

1,260,000 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 a full long-distance migrant that travels mainly via offshore and coastal routes using a number of favoured stopover sites¹. It breeds from June to mid-July in solitary pairs¹, departing the breeding grounds between mid-July and early-September². The species usually occurs in small flocks on migration³ although it may aggregate into larger flocks at stopover sites², and in winter it forages in small to very large flocks¹. Habitat Breeding The species breeds in the high Arctic on barren, stony tundra with well-drained ridges^{1, 3}, gentle slopes or level alluvial plains supporting scattered vegetation of willow Salix spp., Dryas spp. and saxifrage Saxifraga spp. usually less than 200 m above sea-level³. Non-breeding On passage the species may occur on inland freshwater or saline lakes¹ but it is largely coastal during the winter, inhabiting open sandy beaches exposed to the sea, the outer reaches of estuaries, rocky and muddy shores, mudflats¹ and coral reefs⁴. Diet Breeding When breeding the species takes insects (especially adult and larval Diptera, Coleoptera and Lepidoptera) as well as spiders and crustaceans¹. On arrival on the breeding grounds the species may also complement its diet with plant matter (e.g. seeds, saxifrage buds, moss and algae)¹ before invertebrate prey becomes available³. Non-breeding During the winter its diet consists of small molluscs, crustaceans, polychaete worms and adult, larval and pupal insects (e.g. Diptera, Coleoptera, Lepidoptera, Hemiptera and Hymenoptera), as well as occasionally fish and carrion¹. Breeding site The nest is a shallow depression on the bare earth¹ of stony well-drained ridges, gentle slope or level alluvial plains³.

Threats The species is sensitive to disturbance on beaches¹ (e.g. from recreational activities and free-running dogs⁷), and is susceptible to avian influenza so may be threatened by future outbreaks of the virus⁵. In the Chinese, North Korean and South Korean regions of the Yellow Sea (East Asian flyway route) this species is threatened by the degradation and loss of wetland habitats through environmental pollution, reduced river flows and human disturbance⁶.

References 1. del Hoyo et al. (1996). 2. Hayman et al. (1986). 3. Johnsgard (1981). 4. Urban et al. (1986). 5. Melville and Shortridge (2006). 6. Kelin and Qiang (2006). 7. Thomas et al. (2003).

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 (2010) Species factsheet: Calidris alba. Downloaded from http://www.birdlife.org on 9/9/2010

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.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

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