Calidris mauri (Cabanis, 1857)
Geographical variation: Nil
The western sandpiper is a small, Arctic-breeding shorebird that rarely makes it to New Zealand. However, in North America, particularly along the Pacific Coast, it is one of the most abundant waders. In recent decades it was thought that their numbers were declining sharply. However, recent research suggests that the decrease in numbers does not represent a true population decline, but rather reflects changes in the birds’ migratory behaviour. It is believed that due to the recovery of their primary predator, peregrine falcons, western sandpipers (and likely many other species of waders) are using the landscape differently than they were at the end of the last century, and thus many are not being counted during annual surveys.
The western sandpiper is a small sandpiper with a relatively long, slightly down curved bill, slightly drooped at the tip. It has pale grey upperparts and white underparts. The upper breast has fine light grey streaking. The bill and legs are black. During the breeding season the crown, cheeks, and scapulars become bright rufous and the breast becomes heavily spotted.
Voice: a high-pitched, raspy cheet. Western sandpipers often twitter while feeding.
Similar species: the western sandpiper is easily confused with the other small peeps (i.e., stints and other small sandpipers). However its upperparts are grey and lack the brown hues that many other species possess (e.g., red-necked and little stints, Baird’s and least sandpipers); furthermore the western sandpiper’s bill is heavier and has more of a downward curve. These bill characteristics are shared with broad-billed sandpipers, which have olive-green legs (cf. black in western sandpiper).
Distribution and habitat
Western sandpipers breed primarily in western Alaska and eastern Siberia and overwinter from southern North America to northern South America.
The western sandpiper is an extremely abundant species, with a total population estimated at 6.5 million birds.
New Zealand records
There are six accepted records of western sandpiper in New Zealand, all of single birds: Farewell Spit (October 1964), Rangaunu Harbour, Far North (November 1970), Firth of Thames (1970-71, November 1984), and Parengarenga Harbour (April 1976, January 1979).
Behaviour and ecology
The western sandpiper is a typical peep. Birds spend much of diurnal low tides feeding on mudflats and roosting during high tide and at night. They are gregarious, and are usually found with other waders.
During the non-breeding season western sandpipers feed primarily on biofilm and small marine invertebrates, such as polychaetes and crustaceans.
Blackburn, A.; Bell, B.D. 1965. A record of the western sandpiper on Farewell Spit. Notornis 12: 109-110.
Edgar, A.T. 1971. Sightings of rare waders in the Far North. Notornis 18: 116-117.
Franks, S.; Lank, D.B.; Wilson, W.H. Jr. 2020. Western sandpiper (Calidris mauri), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.
Heather, B.D.; Robertson, H.A. 2005. The field guide to the birds of New Zealand. Penguin Books, Auckland.
Hope, D.D.; Lank, D.B.; Smith, B.D.; Ydenberg, R.C. 2011. Migration of two Calidris sandpiper species on the predator landscape: how stopover time and hence migration speed vary with geographical proximity to danger. Journal of Avian Biology 42: 523-530.
Kuwae, T.; Beninger, P.G.; Decottignies, P.; Mathot, K.J.; Lund, D.R.; Elner, R.W. 2008. Biofilm grazing in a higher vertebrate: the western sandpiper, Calidris mauri. Ecology 89: 599-606.
Sibley, D.A. 2000. The Sibley guide to birds. Alfred A. Knopf, New York.
Ydenberg, R. C.; Butler, R. W.; Lank, D. B.; Smith, B. D.; Ireland, J. 2004. Western sandpipers have altered migration tactics as peregrine falcon populations have recovered. Proceedings of the Royal Society B 271: 1263-1269.
Jamieson, S.E. 2013. Western sandpiper. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz
- Breeding season
- Egg laying dates