Calidris pusilla


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Calidris pusilla
Species Authority: (Linnaeus, 1766)
Common Name(s):
English Semipalmated Sandpiper

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Taylor, J. & Butchart, S.
Contributor(s): Andres, B., Mizrahi, D., Brown, A. & Lesterhuis, A.
Facilitator/Compiler(s): Butchart, S., Ekstrom, J., Symes, A.
This species has been uplisted to Near Threatened because it is estimated to have undergone a moderately rapid decline over the past three generations (22 years). Over-exploitation in the non-breeding range (in particular in Suriname) may be the principal driver of declines, with eastern-breeding populations also potentially declining due to reduced food supply at key staging sites, but further information on the rate and drivers of declines is needed.

Geographic Range [top]

Range Description: Calidris pusilla is a common breeder in the Arctic and subarctic from far-eastern Siberia (Russia) east across Alaska (USA) and northern Canada to Baffin Island and Labrador (Chandler 2009). In the non-breeding season the species uses coastal estuarine habitats, wintering on the Pacific coast from Mexico to Peru, and on the Atlantic coast from the Yucatan and the West Indies south to central Argentina, with large non-breeding concentrations occurring along the coast of Suriname and French Guiana (del Hoyo et al. 1996, Chandler 2009, D. Mizrahi in litt. 2009). The population was formerly estimated at 3.5 million individuals, but this was revised downwards to 2.2 million individuals in 2006 (Morrison et al. 2006, A. Lesterhuis in litt. 2009) assuming annual declines of 5% in 75% of the North American population. Trends are hard to quantify, but aerial surveys conducted along the coasts of Suriname and French Guiana suggest that the non-breeding population in the region could have declined by c.80% between the early 1980s and 2008, from c.2 million to c.400,000 individuals; the possibility that there has been a shift in the wintering range seems unlikely but has not been completely ruled out (D. Mizrahi in litt. 2009).
Anguilla; Antigua and Barbuda; Argentina; Aruba; Bahamas; Barbados; Belize; Bermuda; Bonaire, Sint Eustatius and Saba; Brazil; Canada; Cayman Islands; Chile; Colombia; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Ecuador; El Salvador; French Guiana; Grenada; Guadeloupe; Guatemala; Guyana; Haiti; Honduras; Jamaica; Martinique; Mexico; Montserrat; Nicaragua; Panama; Paraguay; Peru; Puerto Rico; Russian Federation; Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Pierre and Miquelon; Saint Vincent and the Grenadines; Sint Maarten (Dutch part); Suriname; Trinidad and Tobago; Turks and Caicos Islands; United States; Uruguay; Venezuela, Bolivarian Republic of; Virgin Islands, British; Virgin Islands, U.S.
Albania; Denmark; Djibouti; France; Germany; Greenland; Iceland; Ireland; Israel; Mauritania; Morocco; Netherlands; Portugal; Spain; Sweden; United Kingdom
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population was formerly estimated at 3.5 million individuals, but this was revised downwards to 2.2 million individuals in 2006 (Morrison et al. 2006, A. Lesterhuis in litt. 2009) assuming annual declines of 5% in 75% of the North American population.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: It breeds in high and low Arctic and subarctic wet sedge or heath tundra, oftern near pools, rivers and lakes (del Hoyo et al. 1996). In the non-breeding season it is mainly coastal, favouring sandy beaches and intertidal mudflats, sometimes also shallow lagoons and saltmarsh (del Hoyo et al. 1996). On migration also at inland wetlands, lake edges etc (del Hoyo et al. 1996). Food is mainly chironomid larvae in the breeding season, along with other small invertebrates and seeds. Various small aquatic, marine and terrestrial invertebrates taken on migration, including horseshoe crab Limulus polyphemus eggs on spring migration in eastern USA (del Hoyo et al. 1996). Makes non-stop flights of up to 4,000 km on migration, with flocks of up to 350,000 gathering at key stopover sites (del Hoyo et al. 1996).
Systems: Terrestrial; Freshwater; Marine

Threats [top]

Major Threat(s): Hunting of shorebirds in northern South America, which is legal in French Guiana but illegal in Suriname, is widespread and thus a potential threat to C. pusilla. Shorebirds killed by hunters in Suriname are estimated to number several tens of thousands annually, involving mainly C. pusilla and Tringa flavipes: if 20,000 C. pusilla were removed from a population of two million annually (1% decrease, net after recruitment), the decline would amount to some 26% over 30 years, independent of other mortality, suggesting hunting could be a significant factor in the observed declines (Morrison et al. 2012). Poaching in Suriname may have increased over the last c.20 years owing to improvements in weaponry and transportation. Another potential threat is the harvesting of horseshoe crabs Limulus polyphemus in Delaware Bay, an area which reportedly sees the passage of c.60% of the total population of C. pusilla during the spring migration. The species feeds primarily on horseshoe crab eggs during episodes of rapid mass accumulation, but harvest pressure from 1995-2005 dramatically reduced egg availability (Mizrahi et al. 2012). Significant changes in the intertidal profile, for unknown reasons, have taken place along the coast of the Guianas, although numbers of birds were also lower in areas with no obvious changes in mudflat area (Morrison et al. 2012). Use of pesticides in agricultural areas such as rice fields may affect shorebirds using those habitats directly, and drainage of pesticides into coastal areas and onto mudflats also has the potential to affect shorebirds (Morrison et al. 2012). Small-scale gold mining has increased considerably in the northern South American wintering range, and mercury, which is used in the extraction process and can reach the coast via the rivers, has the potential to affect shorebirds in coastal areas (Morrison et al. 2012). Oil exploration has also begun in Suriname and Guyana, with spills representing a further potential threat. Increasing frequency and severity of hurricanes during southbound migration may be causing increased mortality during this period (Morrison et al. 2012).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
No species-specific actions are known. Hunting of shorebirds is illegal in Suriname, but this is poorly enforced. An adaptive management plan for Delaware Bay was formally adopted by the Atlantic States Marine Fisheries Commission in 2012. The plan links harvest decisions to information on the welfare of both horseshoe crab and Red Knot Calidris canutus population levels as well as the use of crabs for bait and by the medical industry, and calls for crab harvest levels to be regularly adjusted in response to data on Red Knot and horseshoe crab populations.

Conservation Actions Proposed
Carry out systematic monitoring in breedng areas, key staging sites and wintering sites. Evaluate key threats, in particular mortality from hunting. Campaign for better enforcement of hunting regulations and the introduction of these where they do not currently exist. Support adaptive management plan for horseshoe crab harvest in Delaware Bay.

Citation: BirdLife International 2012. Calidris pusilla. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 29 August 2015.
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