Western Sandpiper
Calidris mauri

Conservation status | Still abundant, but vulnerable because high percentage of population may stop during migration at a few key points, such as Copper River Delta in Alaska. Declining numbers of migrants have been documented in some areas. |
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Family | Sandpipers |
Habitat | Shores, beaches, mudflats; in summer, dry tundra. Migrants and wintering birds are typically on open shorelines, mudflats, sandy beaches, tidal estuaries. In winter mostly along coast, few remaining inland then. Breeds on tundra slopes, choosing dry sites with low shrub layer and with marshes nearby for feeding. |
Photo Gallery
Feeding Behavior
Forages by walking in shallow water or on mud and probing in mud with bill; also feeds by searching visually and picking up items from surface of shore.
Eggs
4, sometimes 3, perhaps rarely 5. Whitish to brown, with darker brown spots. Incubation is by both parents, about 21 days. At first, female incubates from late afternoon to mid-morning, male only during mid-day, but male's proportion increases later. Female sometimes departs before eggs hatch. Young: Downy young leave nest a few hours after hatching. Sometimes both parents care for the chicks, but often the female deserts them after a few days, leaving the male to care for the young. Young feed themselves. Age at first flight about 17-21 days.
Young
Downy young leave nest a few hours after hatching. Sometimes both parents care for the chicks, but often the female deserts them after a few days, leaving the male to care for the young. Young feed themselves. Age at first flight about 17-21 days.
Diet
Includes insects, crustaceans, mollusks, marine worms. On breeding grounds, eats mostly flies and beetles, also other insects, spiders, small crustaceans. Diet in migration and winter varies. On coast eats many amphipods and other crustaceans, small mollusks, marine worms, insects. Inland migrants eat mostly insects, some seeds.
Nesting
Male sings while performing display flight over breeding territory. On ground, unmated male approaches female in hunched posture, tail raised over back; repeatedly gives trilled call. Nest site is on ground, usually under low shrub or grass clump. Nest is shallow depression with sparse lining of sedges, leaves, lichens. Male makes several nest scrapes, female chooses one.
Illustration © David Allen Sibley.
Learn more about these drawings.
Text © Kenn Kaufman, adapted from
Lives of North American Birds
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Migration
From breeding grounds in Alaska and eastern Siberia, migrates southeast to wintering areas on both coasts of North and South America. Apparently migrates in series of short to moderate flights, without long overwater flights of some shorebirds.

- All Seasons - Common
- All Seasons - Uncommon
- Breeding - Common
- Breeding - Uncommon
- Winter - Common
- Winter - Uncommon
- Migration - Common
- Migration - Uncommon
See a fully interactive migration map for this species on the Bird Migration Explorer.
Learn moreSongs and Calls
A soft cheep or kreep, higher and thinner than that of Semipalmated.Learn more about this sound collection.
How Climate Change Will Reshape the Range of the Western Sandpiper
Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.
Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.
Climate threats facing the Western Sandpiper
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.