Species

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 is extremely 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.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls.
AOU. 1998. Check-list of North American birds. American Ornithologists' Union, Washington, D.C.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Taxonomic note
Haematopus ostralegus and H. finschi (Sibley and Monroe 1990, 1993), cross-regional species, are retained as separate species contra Turbott (1990) who include finschi as a subspecies of H. ostralegus.

Population justification
The global population is estimated to number c.1,100,000-1,200,000 individuals (Wetlands International 2006), while national population estimates include: c.100-10,000 breeding pairs, c.1,000-10,000 individuals on migration and c.1,000-10,000 wintering individuals in China; < c.50 individuals on migration and < c.50 wintering individuals in Taiwan; c.100-10,000 breeding pairs in Korea; < c.1,000 wintering individuals in Japan and c.100-10,000 breeding pairs and c.50-1,000 individuals on migration in Russia (Brazil 2009).

Trend justification
The overall population trend is decreasing, although some populations have unknown trends (Wetlands International 2006).

Ecology
Behaviour Most populations of this species are fully migratory, inland breeders moving to the coast for the winter (del Hoyo et al. 1996). The species breeds from April to July (Hayman et al. 1986) in solitary pairs or small groups (Flint et al. 1984), during the winter foraging singly or in small groups of up to 10 individuals (Snow and Perrins 1998) and with larger flocks often forming in major bays and estuaries and at roosting sites (Hayman et al. 1986, del Hoyo et al. 1996, Snow and Perrins 1998). Habitat Breeding The species breeds on coastal saltmarshes, sand and shingle beaches (del Hoyo et al. 1996), dunes, cliff-tops with short grass (Hayman et al. 1986) and occasionally rocky shores (del Hoyo et al. 1996), as well as inland along the shores of lakes, reservoirs and rivers (Hayman et al. 1986) or on agricultural (del Hoyo et al. 1996) grass and cereal fields, often some distance from water (Hayman et al. 1986). Non-breeding Outside of the breeding season the species is chiefly coastal, frequenting estuarine mudflats, saltmarshes and sandy and rocky shores (del Hoyo et al. 1996). Diet When foraging on soft intertidal substrates bivalves and gastropods are the most important food items for this species (del Hoyo et al. 1996). Polychaetes and crustaceans are more important in estuaries however, and molluscs (e.g. mussels, limpets and whelks) are most important on rocky shores (del Hoyo et al. 1996). When inland, prey such as earthworms and insect larvae (e.g. caterpillars and cranefly larvae) are also taken (del Hoyo et al. 1996). Breeding site The nest is a shallow scrape on the ground (del Hoyo et al. 1996) often on raised surfaces (e.g. earth banks) (Hayman et al. 1986) in the open or in short vegetation (Snow and Perrins 1998) on cultivated or uncultivated land, cliff-tops, rocky outcrops or clearings in taller vegetation including woods and moorland (Snow and Perrins 1998). Management information The breeding numbers of this species may decline if cattle grazing regimes are implemented on coastal grassland, possibly as a result of changes in food availability and increased predation risks (Olsen and Schmidt 2004). Removing large numbers of gulls (e.g. Larus argentatus and Larus fuscus) from islands may attract higher breeding numbers of the species but may not improve the overall breeding conditions (Harris and Wanless 1997). There is also evidence that the creation of large marine protected areas (MPAs) to protect this species from the threat of anthropogenic shellfish over-fishing may not be an effective management or conservation technique on a global scale, especially if over-fishing continues to occur in adjacent areas (Verhulst et al. 2004).

Threats
The main threat to the species is the over-fishing of benthic shellfish and the resulting disappearance of intertidal mussel and cockle beds (Atkinson et al.2003, Verhulst et al. 2004, Ens 2006). The species is also threatened by habitat degradation on its wintering grounds due to land reclamation, pollution, human disturbance (Kelin and Qiang 2006) (e.g. from construction work) (Burton et al. 2002), coastal barrage construction (Burton 2006) and reduced river flows (Kelin and Qiang 2006). The species is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006).

Related state of the world's birds case studies

• Commercial shellfisheries can negatively impact migratory waterbirds

References
Flint, V. E.; Boehme, R. L.; Kostin, Y. V.; Kuznetsov, A. A. 1984. A field guide to birds of the USSR. Princeton University Press, Princeton, New Jersey.

Hayman, P.; Marchant, J.; Prater, A. J. 1986. Shorebirds. Croom Helm, London.

del Hoyo, J.; Elliott, A.; Sargatal, J. 1996. Handbook of the Birds of the World, vol. 3: Hoatzin to Auks. Lynx Edicions, Barcelona, Spain.

Snow, D. W.; Perrins, C. M. 1998. The Birds of the Western Palearctic vol. 1: Non-Passerines. Oxford University Press, Oxford.

Atkinson, P. W.; Clark, N. A.; Bell, M. C.; Dare, P. J.; Clark, J. A.; Ireland, P. L. 2003. Changes in commercially fished shellfish stocks and shorebird populations in the Wash, England. Biological Conservation 114: 127-141.

Burton, N. H. K. 2006. The impact of the Cardiff Bay barrage on wintering waterbirds. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), aterbirds around the world, pp. 805. The Stationary Office, Edinburgh, UK.

Ens, B. J. 2006. The conflict between shellfisheries and migratory waterbirds in the Dutch Wadden Sea. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 806-811. The Stationary Office, Edinburgh, UK.

Kelin, C.; Qiang, X. 2006. Conserving migratory shorebirds in the Yellow Sea region. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 319. The Stationery Office, Edinburgh, UK.

Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian-Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK.

Burton, N. H. K.; Rehfisch, M. M.; Clark, N. A. 2002. Impacts of Disturbance from Construction Work on the Densities and Feeding Behavior of Waterbirds using the Intertidal Mudflats of Cardiff Bay, UK. Environmental Management 30(6): 865-871.

Harris, M. P.; Wanless, S. 1997. The effect of removing large numbers of gull Larus spp. on an island population of oystercatchers Haematopus ostralegus: implications for management. Biological Conservation 82: 167-171.

Verhulst, S.; Oosterbeek, K.; Rutten, A. L.; Ens, B. J. 2004. Shellfish fishery severely reduces condition and survival of oystercatchers despite creation of large marine protected areas. Ecology and Society 9(1): unpaginated.

Olsen, H.; Schmidt, N. M. 2004. Impacts of wet grassland management and winter severity on wader breeding numbers in eastern Denmark. Basic and Applied Ecology 5: 203-210.

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

Hear sounds for this species from xeno-canto, the community database of shared bird sounds from around the world.

View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Butchart, S., Ekstrom, J., Malpas, L.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2013) Species factsheet: Haematopus ostralegus. Downloaded from http://www.birdlife.org on 20/06/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/06/2013.

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

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

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