A migratory wading bird of the genus Arenaria (family Scolapacidae), about 20 cm long with a stocky body and a short, slightly upturned bill that it uses to turn over stones along the shore in search of invertebrates. There are two species, the ruddy turnstone (A. interpres) with a northern hemisphere circumpolar distribution, wintering in South Africa and Australia, and the black turnstone (A. melanocephala), which breeds in Alaska and winters on the Pacific coast of the USA.