The Sanderling (Calidris alba) is a small, lively wader familiar to most beachgoers as the bird that runs back and forth in the swash zone of sandy beaches. It is about 17–21 cm long with a wingspan of 36–39 cm and a weight of 40–80 g, and in winter plumage it is remarkably pale — the underside pure white, the upperside pale pearl-grey, with a dark patch often visible at the bend of the wing, while the legs and short, straight bill are black. A reliable mark is that, unlike other small waders in the genus Calidris, the Sanderling lacks a hind toe. In summer plumage the head, breast and upperside turn rusty brown with dark mottling, making the bird considerably darker and more patterned than in winter. Overall it gives the impression of a round, quick, short-legged wader that looks strikingly white as it runs along the shoreline, and its call is a short, sharp, somewhat hard "plitt" or "kvitt", often heard as small flocks take off and fly along the beach.
Sanderlings breed circumpolar on high Arctic tundra — in Greenland, Svalbard and northern Siberia — nesting in a simple ground scrape in sparsely vegetated, often gravelly terrain near the coast, with the precocial chicks foraging for themselves soon after hatching during the brief Arctic summer. They winter along coasts as far away as Africa, South America and Australia, and in Sweden the species occurs only as a passage migrant, never breeding; hundreds to thousands rest along the coasts, especially on sandy beaches of the west coast and south, classified as Least Concern. Its defining technique is to follow the waves in and out, running rapidly back and forth to snatch small crustaceans, worms and other invertebrates uncovered or washed up as the water retreats — a "beach-dancing" behaviour, the whole flock moving as one, that makes the species easy to identify even from a distance.
Read about this species in Swedish →