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Red Knot Calidris canutus

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: # _the_WP15.xls#.
Christidis, L.; Boles, W. E. 2008. Systematics and taxonomy of Australian birds. CSIRO Publishing, Collingwood, Australia.
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.
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
SACC. 2006. A classification of the bird species of South America. Available at: #
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

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

Trend justification
The overall population trend is decreasing, although some populations may be stable and others have unknown trends (Wetlands International 2006). This species has undergone a small or statistically insignificant decrease over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007) Note, however, that these surveys cover less than 50% of the species's range in North America.

Behaviour This species is a full long-distance migrant that utilises few stopover sites or staging areas (del Hoyo et al. 1986). The species breeds from June to August (Hayman et al. 1986) in solitary pairs (del Hoyo et al. 1986), travelling in flocks on migration (Hayman et al. 1986) and remaining highly gregarious in winter often foraging in flocks of 300-10,000 individuals (del Hoyo et al. 1986) at select feeding and roosting sites (Hayman et al. 1986). Habitat Breeding The species breeds in the high Arctic (del Hoyo et al. 1986) on dry upland tundra including weathered sandstone ridges, upland areas with scattered willows Salix spp., Dryas spp. and poppy, moist marshy slopes and flats in foothills, well-drained slopes hummocked with Dryas spp. (Johnsgard 1981) and upland glacial gravel close to streams or ponds (del Hoyo et al. 1986). Non-breeding Outside of the breeding season the species is strictly coastal, frequenting tidal mudflats or sandflats, sandy beaches of sheltered coasts, rocky shelves, bays, lagoons and harbours, occasionally also oceanic beaches and saltmarshes (del Hoyo et al. 1986). Diet Breeding During the breeding season the species's diet consists predominantly of insects (mainly adult and larval Diptera, Lepidoptera, Trichoptera, Coleoptera and bees) as well as spiders, small crustaceans, snails and worms (del Hoyo et al. 1986). When it first arrives on the breeding grounds however, the species is dependant upon vegetation (including the seeds of sedges, horsetails Equisetum spp. and grass shoots) owing to the initial lack of insect prey (Johnsgard 1981). Non-breeding Outside of the breeding season the species takes intertidal invertebrates such as bivalve and gastropod molluscs, crustaceans (del Hoyo et al. 1986) (e.g. horseshoe crab Limulus spp. eggs) (Karpanty et al. 2006), annelid worms and insects, rarely also taking fish and seeds (del Hoyo et al. 1986). Breeding site The nest is an open shallow depression (Flint et al. 1984) either positioned on hummocks surrounded by mud and water or on stony or gravelly ground (Johnsgard 1981) on open vegetated tundra or stone ridges (del Hoyo et al. 1986).

The species is vulnerable to extensive land reclamation projects that encroach upon staging areas in Western Europe (del Hoyo et al. 1986), and is threatened by the over-exploitation of shellfish (del Hoyo et al. 1986, Goldfeder and Blanco 2006) which leads directly and indirectly to reductions in prey availability (del Hoyo et al. 1986). The species also suffers from disturbance in the non-breeding season as a result of tourism (Goldfeder and Blanco 2006), foot-traffic on beaches (Burton et al. 2002), recreational activities and over-flying aircraft, which together reduce the size of available foraging areas (del Hoyo et al. 1986). It is also potentially threatened by industrial pollution and oil exploration (Argentina) (Goldfeder and Blanco 2006), and is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006). Utilisation The species is hunted illegally in New Zealand (del Hoyo et al. 1986).

Related state of the world's birds case studies

Beaumont, L. J.; McAllan, I. A. W.; Hughes, L. 2006. A matter of timing: changes in the first date of arrival and last date of departure of Australian migratory birds. Global Change Biology 12: 1339-1354.

Brazil, M. 2009. Birds of East Asia: eastern China, Taiwan, Korea, Japan, eastern Russia. Christopher Helm, London.

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.

Delany, S.; Scott, D. 2006. Waterbird population estimates. Wetlands International, Wageningen, The Netherlands.

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.

Goldfeder, S. D.; Blanco, D. E. 2006. The conservation status of migratory waterbirds in Argentina: towards a national strategy. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 189-194. The Stationary Office, Edinburgh, UK.

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

Johnsgard, P. A. 1981. The plovers, sandpipers and snipes of the world. University of Nebraska Press, Lincoln, U.S.A. and London.

Karpanty, S. M.; Fraser, J. D.; Berkson, J.; Niles, L. J.; Dey, A.; Smith, E. P. 2006. Horseshoe Crab Eggs Determine Red Knot Distribution in Delaware Bay. Journal of Wildlife Management 70(6): 1704-1710.

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.

Further web sources of information
Detailed regional assessment and species account from the European Red List of Birds (BirdLife International, 2015)

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

Explore HBW Alive for further information on this species

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

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

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

Recommended citation
BirdLife International (2015) Species factsheet: Calidris canutus. Downloaded from on 04/10/2015. Recommended citation for factsheets for more than one species: BirdLife International (2015) IUCN Red List for birds. Downloaded from on 04/10/2015.

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

ARKive species - Red knot (Calidris canutus) 0

Key facts
Current IUCN Red List category Least Concern
Family Scolopacidae (Sandpipers, Snipes, Phalaropes)
Species name author (Linnaeus, 1758)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 1,600,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change
- 2015 European Red List assessment