Calidris ptilocnemis (Coues, 1873)

Scientific Nomenclature

This species has the scientific name Calidris ptilocnemis (Coues, 1873).

Adult Morphology

Adult rock sandpipers have short yellow legs and a medium, thin dark bill. Their upper body is dark with a slight purplish gloss, and their underparts are mainly white. The breast is smeared with grey, and the rump is black.

Subspecies Plumage Variation

The nominate subspecies from the Pribilof Islands has a bold black belly patch when in breeding plumage; the remaining three subspecies more closely resemble the purple sandpiper than the nominate subspecies.

Winter Migration Range

In winter, these birds migrate south to rocky ice-free Pacific coasts.

Leapfrog Migration Pattern

Subspecies engage in leapfrog migration for winter, with more northerly breeders moving to wintering grounds south of those of more southerly breeders.

Breeding Habitat

The species breeds in tundra habitats, typically favoring drier, more desolate areas with limited vegetation like lichen, moss, and sparse grasses.

Winter Flocking Behavior

It can form quite large flocks during winter.

Non-breeding Diet and Survival

Rock sandpipers that spend the non-breeding season in the Pacific Basin, Alaska, must endure harsh conditions and rely on high quality prey, especially their primary prey, the bivalve Macoma balthica.