By far the most numerous shorebird in the Pribilofs, at all times of the tour season, this species is an abundant breeder on the island. The nominate subspeciesCalidris ptilocnemis ptilocnemisoccurs on the Pribilof and Saint Matthew and Hall Islands, and winters principally in the Cook Inlet of south-coastal Alaska. This subspecies is characterized by its large size, bright orangey upperparts, bold white wingstripe that extends through the primaries and less black on the breast than other subspecies of Rock Sandpiper. During summer the frog-like croaks and harsh call notes of this species form a near constant auditory background through the grassy center of the island. There is some indication that the Saint Paul population of this species is currently undergoing a substantial decline, due mostly to habitat alteration and destruction by the herd of exotic Reindeer that are on the island. The mainland Alaskan subspeciesCalidris ptilocnemis tschuktschorumis annual, especially in fall and can be identified by its smaller size, darker upperparts and underparts and shorter white wing stripe.