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The Ivory Bill·Birds·Shorebirds
 

White-rumped Sandpiper, Calidris fuscicollis

White-rumped sandpiper on a large rock scanning the shore

White-rumped Sandpipers are shorebirds that breed in tundra habitats in the Arctic regions of North America, primarily in northern Canada and Alaska, from late May to early August.

White-rumped Sandpipers are commonly found in wet, grassy tundra areas with scattered shrubs, where insects such as midges and other invertebrates are abundant during the summer breeding season.

They forage in shallow wetlands, marshy areas, and along the edges of ponds and streams for insects, spiders, small crustaceans, and occasionally seeds. They may also feed on small mollusks and plant material.

White-rumped Sandpipers have a unique foraging technique that involves probing the mud with their bills to locate prey by touch. Their slightly longer wings and rapid flight allow them to cover large areas efficiently in search of food.

Courtship involves elaborate displays where males perform flight songs, consisting of musical trills and whistles, while circling above the female. On the ground, males may engage in strutting displays, puffing out their chests and fanning their tails.

Nest building is done by the female, who creates a shallow scrape on the ground, often lined with moss, grass, and lichens. These nests are usually well-hidden among low vegetation.

Egg laying occurs from early to mid-June, with the female typically laying four eggs. Incubation lasts about 21 days and is primarily performed by the female. Upon hatching, the chicks are precocial and can leave the nest within hours. Initial diets for chicks consist of small insects and other invertebrates provided by the female.

Chicks learn to forage under the watchful eyes of the adults, gradually becoming more independent. They face vulnerabilities such as predation from gulls and jaegers and exposure to harsh weather conditions.

Chick fledging occurs about three weeks after hatching, with continued guidance from adults as the chicks improve their foraging skills. Their diet evolves to include a broader range of invertebrates as they grow.

White-rumped Sandpipers undertake long migratory journeys, leaving their breeding grounds in late July to early August. They follow specific flyways, traveling through North America, Central America, and the Caribbean to reach wintering regions in South America, including Argentina, Brazil, and Uruguay.

Wintering habitats include coastal mudflats, estuaries, and sandy beaches, where they forage for small crustaceans, marine worms, and other intertidal invertebrates. Their diet during winter is more varied, reflecting the rich food resources of these coastal areas.

White-rumped Sandpipers typically leave their wintering grounds and begin their northward migration in March, arriving back at their Arctic breeding grounds by late May, timed with the availability of abundant insect prey.