The ruddy turnstone (Arenaria interpres) is a small cosmopolitan wading bird, one of two species of turnstone in the genus Arenaria. It is now classified in the sandpiper family Scolopacidae but was formerly sometimes placed in the plover family Charadriidae. It is a highly migratory bird, breeding in northern parts of Eurasia and North America, and flying south to winter on coastlines almost worldwide. It is the only species of turnstone in much of its range and is often known simply as turnstone.
Taxonomy The ruddy turnstone was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Tringa interpres. The species is now placed together with the black turnstone in the genus Arenaria that was introduced by the French zoologist Mathurin Jacques Brisson in 1760 with the ruddy turnstone as the type species. The genus name arenaria is from Latin arenarius, "inhabiting sand", from arena, "sand". The specific interpres means "messenger"; when visiting Gotland in 1741, Linnaeus thought that the Swedish word Tolkcode: swe promoted to code: sv , meaning "interpreter" applied to this species, but in the local dialect the word means "legs" and is used for the redshank. Two subspecies are recognised:
A. i. interpres (Linnaeus, 1758) – breeds in northeast Canada, Greenland, north Europe to northeast Siberia and west Alaska; winters in west, south Europe, Africa, south, east Asia, Australasia, Pacific islands, west US and west Mexico A. i. morinella (Linnaeus, 1766) – breeds in northeast Alaska and north Canada; winters in south US to South America
Description It is a fairly small and stocky bird, 22–24 cm (8.7–9.4 in) long with a wingspan of 50–57 cm (20–22 in) and a weight of 85–150 g (3.0–5.3 oz). The dark, wedge-shaped bill is 2–2.5 cm (0.79–0.98 in) long and slightly upturned. The legs are fairly short at 3.5 cm (1.4 in) and are bright orange. In all seasons, the plumage is dominated by a harlequin-like pattern of brown, black and white. Breeding birds have reddish-brown upper parts with black markings. The head is mainly white with black streaks on the crown and a black pattern on the face. The breast is mainly black apart from a white patch on the sides. The rest of the underparts are white. In flight it reveals a white wingbar, white patch near the base of the wing and white lower back, rump and tail with dark bands on the uppertail-coverts and near the tip of the tail. The female is slightly duller than the male and has a browner head with more streaking. Non-breeding adults are duller than breeding birds and have dark grey-brown 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 A. i. morinella are marginally 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.
Distribution 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 Baffin Island. A. i. interpres breeds in western Alaska, Ellesmere Island, Greenland, Norway, Denmark, Sweden, Finland, Estonia and northern Russia. It formerly bred on the Baltic coast of Germany and has possibly bred in Scotland and the Faroe Islands. In the Americas, the species winters on coastlines from Washington and Massachusetts southwards to the southern tip of South America although it is scarce in southern parts of Chile and Argentina and is only an unconfirmed vagrant in the Falkland Islands. In Europe, it winters in western regions from Iceland, Norway and Denmark southwards. Only small numbers are found on Mediterranean coasts. In Africa, it is common all the way down to South Africa with good numbers on many offshore islands. In Asia, it is widespread in the south with birds wintering as far north as southern China and Japan (mainly in the Ryukyu Islands). It occurs south to Tasmania and New Zealand and is present on many Pacific islands. Some non-breeding birds remain year round in many parts of the wintering range, with some of those birds still taking on breeding plumage in the spring and summer.
Behaviour
Feeding and diet The ruddy turnstone has a varied diet including carrion, eggs, fish and plant material but it feeds mainly on invertebrates. Insects and their larvae are particularly important in the breeding season. At other times it also takes crustaceans, spiders, 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 to get at the contents within. Ruddy turnstones engage in a variety of behaviours to locate and capture prey. These behaviours can be placed into six general categories:
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