Western Sandpiper (Calidris mauri)

Western Sandpiper

[order] CHARADRIIFORMES | [family] Scolopacidae | [latin] Calidris mauri | [UK] Western Sandpiper | [FR] Becasseau d’Alaska | [DE] Berg-Strandlaufer | [ES] Correlimos de Alaska | [NL] Alaska-strandloper


Monotypic species

Physical charateristics

In breeding plumage, it has a deep rufous crown and cheek patch, and rufous on the wings. It is heavily streaked and spotted on the breast and back. By fall, much of this color has faded or worn off. Its slightly drooping bill, black legs, and bright rufous patches in breeding plumage help distinguish it from similar species like the Least and Semipalmated Sandpipers. The adult in non-breeding plumage is drab grey with a white breast. Juveniles look similar to adults in breeding plumage, but their breasts are not streaked. They have rufous on their backs, but not on their heads or cheeks. Their plumage is not sexually dimorphic, but females have slightly longer bills than males. In flight, they show a white stripe down their wings and white on either side of their tails.

Listen to the sound of Western Sandpiper

[audio:http://www.aviflevoland.nl/sounddb/W/Western Sandpiper.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 28 cm wingspan max.: 33 cm
size min.: 15 cm size max.: 16 cm
incubation min.: 19 days incubation max.: 21 days
fledging min.: 17 days fledging max.: 21 days
broods: 1   eggs min.: 3  
      eggs max.: 5  


North America : North


Most of the population of Western Sandpipers breeds in Alaska, in dry tundra areas with low shrub cover and nearby marshes. During migration, they are mostly coastal, but some migrate across land and stop over at inland wetlands. During coastal migration and in winter, they occur in most shoreline habitats, but prefer mudflats and sandy beaches.


Males typically arrive on the breeding grounds first and establish territories. Monogamous pair bonds form after the females arrive. The male starts several nest scrapes, and the female selects one and lines it with leaves, lichen, and sedge. Both parents incubate the four eggs for 21 days. The young leave the nest within a few hours of hatching and find their own food. The female often deserts the group within a few days of hatching, and joins other post-breeding females in a flock. The male tends the young, and broods them in cold weather until they can fly, at 17 to 21 days.

Feeding habits

During the breeding season, insect larvae are the food of choice. The migration and winter diet is primarily crustaceans, mollusks, marine worms, and other aquatic invertebrates.


This species has a very 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.
Western Sandpiper status Least Concern


Unlike other small Calidris, migration appears as series of shorter flights; flight range c. 600 km. E Siberian birds join Nearctic population on migration. Most migrate down Pacific coast, although significant numbers move through interior North America, with Cheyenne Bottoms as most important interior stopover site, during both spring and autumn. During N migration Copper R Delta functions as key staging site, used by more than 90% of total population; other major spring stopover sites are San Francisco Bay, Grays Harbor, Fraser Delta, Chesterman Beach, Tofino mudflats and Stikine Delta; southbound, Yukon Delta, Kuskokwim Bay and Boundary Bay. On Atlantic coast, common autumn migrant to Puerto Rico. Males winter, on average, closer to breeding grounds, and predominate at start of N migration. In autumn, departure occurs Jul to early Aug; adults precede juveniles, and females slightly precede males. Migrates in huge flocks. Many immatures stay in non-breeding range all year. Arrival on breeding grounds May to mid-Jun.

Distribution map

Western Sandpiper distribution range map

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