Rock Sandpiper

The Rock Sandpiper, Calidris ptilocnemis, is a small, robust shorebird with a preference for the colder climates of the Arctic and subarctic. It is a member of the sandpiper family, Scolopacidae, and shares a close kinship with the Purple Sandpiper. The adult Rock Sandpiper is characterized by short yellow legs and a medium, thin dark bill. Its upperparts are dark with a purplish sheen, while the underparts are predominantly white. A grey wash adorns the breast, and the rump is distinctly black. Notably, the Pribilof Islands subspecies exhibits a striking black belly patch.

Identification Tips

When identifying the Rock Sandpiper, look for the combination of its short yellow legs and the medium-length dark bill. The dark upperparts with a purplish gloss and the white underparts with a greyish breast are key features. The black rump and, in some subspecies, the bold black belly patch are also distinctive.

Habitat

The Rock Sandpiper breeds on the tundra along the Arctic Pacific coast, including Alaska and the Aleutian and Pribilof Islands, as well as in Kamchatka and the Kuril Islands. During the non-breeding season, it migrates to rocky, ice-free Pacific coasts.

Distribution

This species is known to migrate southwards in winter, with a remarkable strategy where more northerly breeding populations move past the wintering grounds of more southerly breeders. They can form sizeable wintering flocks and endure the harsh conditions of the Pacific Basin in Alaska.

Breeding

The Rock Sandpiper's breeding habitat is the northern tundra along the Arctic Pacific coast. They are monogamous, often maintaining pair bonds for several years. They exhibit a preference for nesting on the ground, either elevated on rocks or in damp locations. The male prepares several scrapes, from which the female selects one for laying her clutch of four eggs. Both parents share the responsibility of incubation.

Diet and Feeding

The Rock Sandpiper forages along rocky coasts, feeding primarily on insects, mollusks, marine worms, and some plant material. It is known to feed in water up to its breast and occasionally swims. It roosts on rocks near feeding grounds, just above the reach of high tide.

Conservation status

The IUCN Red List classifies the Rock Sandpiper as Least Concern, indicating that it is not currently at significant risk of widespread decline.