Ruddy turnstone (Arenaria interpres)

Also known as: turnstone
French: Tournepierre à collier
GenusArenaria (1)
SizeLength: 21 - 26 cm (2) (3)
Wingspan: 50 - 57 cm (2) (3)
Weight84 - 190 g (2) (3)

Classified as Least Concern (LC) on the IUCN Red List (1).

The ruddy turnstone is a small, stocky, brightly-patterned shorebird (2) (3) (4) (5), named for its habit of turning over objects such as stones, shells and seaweed to uncover prey hidden beneath (6). During the breeding season, the adult’s striking ‘tortoiseshell’ plumage is reddish-brown with blackish-brown patches on the upperparts, and white on the underparts, with a black and white head, throat, neck and breast. A white rump, back, upper tail and wingbar are conspicuous in flight and contrast with the otherwise dark upperparts. This species has short, usually orangey-red legs, with unwebbed toes, and the beak is short, dark and wedge-shaped, with a slightly upturned tip (2) (3) (4) (5). Non-breeding individuals are much duller and darker, with greyish-brown and blackish upperparts, and grey-brown on the head, neck and breast (2) (3) (4). Juveniles resemble the non-breeding adult, but are browner, with a paler head (2) (3) (5).

In breeding plumage, the female ruddy turnstone can usually be distinguished from the male by the more mottled and streaked crown, slightly duller upperparts, browner back to the neck, and flecking on the breast. There are two subspecies of ruddy turnstone, Arenaria interpres interpres and Arenaria interpres morinella, the latter being slightly smaller, with less black streaking and brighter reddish-brown upperparts (2) (3). The ruddy turnstone can be distinguished from the closely related black turnstone (Arenaria melanocephala) by its reddish plumage, more intricate patterning, and orange rather than dark legs (3) (5). The calls of the ruddy turnstone include a short, staccato tuk-a-tuk and a long, rapid trill (3) (4) (5).

The ruddy turnstone is one of the most northerly breeding shorebird species (3), with a wide breeding range across the Arctic, from Alaska to Greenland, on Svalbard, and from Scandinavia to Siberia. A migratory species, A. i. interpres winters on the coasts of Western Europe, Africa, South Asia, Australasia and South Pacific islands, and on the Pacific coast of North America, while the wintering range of A. i morinella extends from the southern United States, through Central America, the Caribbean and the West Indies, and throughout South America as far as Tierra del Fuego (2) (3) (6) (7).

This species breeds on rocky Arctic coasts and tundra, including stony plains and marshes, near water, and prefers areas that remain damp until late summer. The choice of breeding habitat is strongly influenced by the availability of nearby food resources during nesting and chick-rearing. During the winter, the ruddy turnstone usually inhabits coastal areas, typically on rocky or stony shores, although it sometimes also occurs on sandy beaches, salt marshes and mudflats. During migration, it may also occur inland, for example along lake shores (2) (3) (5) (7).

The ruddy turnstone is an efficient and opportunistic forager, taking advantage of a wide range of food resources, including insects and insect larvae (particularly midges and other flies during the breeding season), spiders, crustaceans, molluscs, worms and other invertebrates, as well as some plant matter such as berries early in the breeding season. This species will even take small fish and birds’ eggs, and will scavenge on carrion and discarded human food (2) (3) (6) (7). A variety of feeding methods are used, including flipping over objects such as stones and seaweed, probing mud and sand with the beak, digging, or pecking food from the surface of rocks. Despite its small size, the ruddy turnstone is capable of pushing and overturning quite large objects, which are sometimes pushed with the breast (2) (3) (5) (6). Ruddy turnstones often forage in close flocks of up to 100 or more birds, and large flocks may form on migration and during the non-breeding season (2) (3) (6) (7).

The ruddy turnstone breeds from around May to early August, usually in solitary, monogamous pairs. The nest is a shallow scrape on the ground, lined with a small amount of vegetation, and often located on a slight ridge or hummock (2) (3) (5) (6) (7). Up to four eggs are laid and are incubated for around 22 days, mainly by the female but also sporadically by the male. The chicks are able to leave the nest and feed themselves within a day of hatching. Although the adults continue to guard the brood for a time, the female leaves after the first week or two, leaving the male to remain with the young until fledging occurs at around 19 to 21 days (2) (3) (6) (8).

All ruddy turnstones migrate south for the winter months, the females leaving the breeding grounds first, followed by the males and then the newly fledged young (2) (3) (6) (8). Immature birds usually remain in the wintering grounds for the first summer, not breeding until at least two years old (2) (3) (6). Studies have shown that ruddy turnstones can undertake impressive journeys, with some recorded flying 7,600 kilometres non-stop from Australia to Taiwan in just 6 days, before continuing to northern Siberia. One bird even completed a return trip to Australia via the Central Pacific, a total round-trip of 27,000 kilometres (9).

The ruddy turnstone has a very large range and is not currently considered at risk of extinction (7). However, the species may face localised threats from pollution, habitat loss through coastal development and recreational activities, nest predation by feral American mink (Neovison vison), and low levels of hunting and trapping (3) (6) (7). Pressures on important stopover areas, such as the overexploitation of horseshoe crabs (Limulus polyphemus) in North America, may also affect critical food supplies during migration, and the species is susceptible to outbreaks of avian influenza. Climate change may also pose a potential future threat (3) (7), possibly affecting the ruddy turnstone’s habitat or food supplies.

The ruddy turnstone is listed on Appendix II of the Convention on Migratory Species (CMS), which aims to conserve migratory species throughout their range (10), and is also listed under the African-Eurasian Waterbird Agreement (AEWA), which calls upon parties to undertake conservation actions to protect bird species that are dependent on wetlands for at least part of their annual cycle (11). As a long-distant migrant, the ruddy turnstone depends on the protection of not only its breeding and wintering areas, but also of critical stopover sites on its migration routes (3). As well as studies into its migration patterns (9), this species would also benefit from population monitoring and further research into its biology and ecology, while measures such as the removal of feral American mink from breeding islands may help to increase breeding success in some areas (7).

To find out more about the ruddy turnstone see:

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  1. IUCN Red List (June, 2010)
  2. del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona.
  3. Nettleship, D.N. (2000) Ruddy turnstone (Arenaria interpres). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
  4. Peterson, R.T., Mountfort, G. and Hollom, P.A.D. (1993) Collins Field Guide: Birds of Britain and Europe. HarperCollins Publishers, London.
  5. The Cornell Lab of Ornithology - All About Birds: Ruddy Turnstone (June, 2010)
  6. Nellis, D.W. (2001) Common Coastal Birds of Florida and the Caribbean. Pineapple Press, Florida.
  7. BirdLife International (June, 2010)
  8. Nettleship, D.N. (1973) Breeding ecology of turnstones Arenaria interpres at Hazen Camp, Ellesmere Island, N.W.T. Ibis, 115(2): 202-217.
  9. BirdLife International: A ruddy long way to fly (June, 2010)
  10. Convention on the Conservation of Migratory Species of Wild Animals (June, 2010)
  11. Agreement on the Conservation of African-Eurasian Migratory Waterbirds (June, 2010)