Ruddy turnstone but it feeds mainly on invertebrates. Insects are particularly important in the breeding season. At other times it also takes crustaceans, molluscs and worms. It often flips over stones and other objects to get at prey items hiding underneath; this behaviour is the origin of the name "turnstone". It usually forages in flocks. They have also been observed preying on the eggs of other bird species such as gulls, terns, ducks, and even other turnstones, though this behaviour is uncommon. In the majority of observed cases, turnstones typically go after undefended or unattended nests, puncturing the shells with their beaks
Ruddy turnstone upperparts with black mottling and a dark head with little white. Juvenile birds have a pale brown head and pale fringes to the upperpart feathers creating a scaly impression. Birds of the subspecies "morinella" are smaller with darker upperparts and less streaking on the crown. The ruddy turnstone has a staccato, rattling call and also a chattering alarm-call which is mainly given during the breeding season. The ruddy turnstone breeds in northern latitudes, usually no more than a few kilometres from the sea. The subspecies "A. i. morinella" occurs in northern Alaska and in Arctic Canada as far east as