Calidris

Calidris is a genus of Arctic-breeding, strongly migratory wading birds in the family Scolopacidae. These birds form huge mixed flocks on coasts and estuaries in winter. They are small to medium-sized sandpipers, long-winged and relatively short-billed; some are difficult to identify because of the similarity between species, and various breeding, non-breeding, juvenile, and moulting plumages. With a few exceptions, they have a fairly stereotypical colour pattern, being brownish above and lighter, usually white or buffy coloured, on much of the underside. They often have a lighter supercilium above brownish cheeks. The species are variously known in English as sandpipers or stints; some have their own unique names, with dunlin, knot, ruff, and sanderling and surfbird. In North America, the smaller species are often known colloquially as peeps.