• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

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#.
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#.
Cramp, S. and 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.
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. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
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: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.html#.
SACC. 2006. A classification of the bird species of South America. Available at: #http://www.museum.lsu.edu/~Remsen/SACCBaseline.htm#.

Population justification: 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, Andres et al. 2012), assuming annual declines of 5% in 75% of the North American population.

Trend justification: This species is conservatively estimated to have declined at a rate approaching 30% over three generations (22 years). Determining the exact population trajectory is very difficult, but aerial surveys along the coasts of Suriname, French Guiana and Guyana (which may support c.85% of the population wintering on the coast of South America) suggest that the non-breeding population may have declined by c.79% between the early 1980s and 2008 (Morrison et al. 2012), while data from the Bay of Fundy show a 68% decline during southbound migration between 1982 and 2005, with the greatest reductions taking place since the mid 1990s.  Preliminary results from surveys off the Brazilian coast (Belem to Baia de Sanadi) in 2011 suggest that declines have also taken place here since 1982, making it unlikely that a southward shift in wintering range accounts for the declines in Suriname and French Guiana (D. Mizrahi in litt. 2011). Long-term population trend indices also suggest that Semipalmated Sandpiper has declined significantly since the 1980s, especially populations migrating along the Atlantic Coast en route to eastern Canadian breeding areas (Mizrahi et al. 2012). Analyses of population trends with migration monitoring data from eastern and central North America for the 35-year period from 1974 to 2009 found trends that were generally negative, but not statistically significant, with counts that decreased between 1985 and 1999, then recovered at least partially through the 2000s (Gratto-Trevor et. al. 2012). However, data from the breeding range suggests that the species was generally increasing or stable in the western and central portions of the range and had an uncertain status in the east (Smith et al. 2012), making the overall picture difficult to determine.

Recommended citation
BirdLife International (2020) Species factsheet: Calidris pusilla. Downloaded from http://www.birdlife.org on 10/04/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 10/04/2020.