Arenaria interpres

Geographic Range

Ruddy turnstones are one of the northernmost breeding shorebirds. They breed in arctic tundra from Alaska, across Canada, Greenland, Scandinavia, the Baltic Islands, and across northern Siberia to the Bering Sea. In winter they are found along coastlines from northern Massachusetts and northern California throughout the Antilles, Central and South America to Tierra del Fuego and along coastlines throughout Europe, Africa, Australia, New Zealand, Southeast Asia, and the Pacific Islands.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native
• oriental oriental
  • native native
• ethiopian ethiopian
  • native native
• neotropical neotropical
  • native native
• australian australian
  • native native
• oceanic islands oceanic islands
  • native native

• Other Geographic Terms
• holarctic holarctic
• cosmopolitan cosmopolitan

Habitat

Ruddy turnstones are found in arctic tundra and rocky coastal areas during the breeding season and along coastlines during winter and migration. Preferred habitats in winter are sandy coastlines and mudflats, but ruddy turnstones are also found on rocky beaches, wetlands, and other intertidal areas.

• Habitat Regions
• temperate temperate
• tropical tropical
• polar polar
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune

• Aquatic Biomes
• coastal coastal

• Other Habitat Features
• estuarine estuarine

Physical Description

Ruddy turnstones are small, robust sandpipers with stout, black, slightly upturned bills. They are 21 to 26 cm long, weighing from 84 and 190 g, and a wingspan of 50 to 57 cm. Plumage in breeding and non-breeding seasons are similar, slightly darker overall in the non-breeding season. Males and females are also similar in appearance. Ruddy turnstones have rufous feathers on their back and dorsal surface of their wings. They have black and brown plumage on the head and interspersed with the rufous areas overall. The belly is white and the legs are bright orange. They have a dark, black band that stretches across the neck and chest, like a bib. In flight they have distinctive white wing stripes and black on the trailing edge of the wing. There are two white stripes along the back and a broad, white rump patch.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes alike

Reproduction

Ruddy turnstones are monogamous. Pairs form on the breeding territory, meeting again in the same territory used the previous year. In one study 16 turnstones kept the same mate each year over a 5 year period. Ruddy turnstones are aggressive, mated pairs initially are aggressive towards each other, even when one or the other returns to the nest. Pair bonds are renewed through courtship displays on the ground and in the air. Displays can be initiated by either females or males. Once the pair bond is established, males and females remain within sight of each other until egg-laying begins.

• Mating System
• monogamous monogamous

Ruddy turnstones arrive on the breeding grounds in late May and early June and establish pair bonds within 7 to 10 days of their arrival and create a nest scrape lined with leaves and lichen and begin laying eggs within a few days after that, usually by mid-June. Egg laying is influenced by the availability of prey and may be delayed if there isn't enough animal foods. Females lay 1 egg each day for the first 3 eggs, with other eggs laid at 1 to 2 day intervals. Locally, females are highly synchronous in egg-laying. Clutches are completed by late June and incubation begins at the 3rd egg laid. Clutches are from 2 to 5, but usually 4, dark brown or olive splotched eggs and incubation is 21 to 24 days long. Young hatch within a day or two of each other. Fledging occurs at 19 to 21 days old, at which point the young are independent. Ruddy turnstone young remain on their wintering grounds throughout their first year after hatching. Young begin to breed in their 2nd year, although breeding may be delayed until 3 or 4 years old.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

Females and males incubate the eggs, but females do most of the incubation and caring for the eggs and nest. Males patrol the nest area and warn the female of the presence of predators, at which point she will move from the nest to distract attention from the eggs. Young ruddy turnstones hatch with downy feathers and are able to walk and begin to find food within a few hours after hatching and the nest is abandoned within a day of hatching. Males and females protect the hatchlings, but the female abandons the brood mid-way through the hatchling period and the male remains to protect the young until they fledge, at 19 to 21 days old. Parents aggressively guard their young and lead them to areas with lots of prey, especially midges , so they can feed themselves. A few days after fledging, usually at 21 to 23 days old, the young are almost at adult sizes and begin their first migration to the wintering grounds.

• Parental Investment
• precocial precocial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • protecting
    • male
    • female

Lifespan/Longevity

The longest lifespan for ruddy turnstones in the wild is an individual that lived to 19.7 years. Average lifespan in Finland was estimated at 6 to 7 years. Survival rates in the first year are estimated at 45 to 58% in some areas. Annual survival of adults is estimated at 66 to 85% in some areas. Eggs and hatchlings are vulnerable to cold weather, damage to eggs during incubation, and predation.

Behavior

Ruddy turnstones are social outside of the breeding season, forming small groups of tens to many thousands and mixing with other species of shorebirds. During the breeding season ruddy turnstones are aggressive and territorial. They are also aggressive outside of the breeding seasons towards other shorebirds competing for food. They actively defend a small personal space from other shorebirds. To intimidate other shorebirds they use threat display, involving raising their feathers and rushing at the other bird along with calling. Ruddy turnstones can run quickly and use their robust legs, claws, and bills to dig up prey. They can fly quickly for long distances, more than 1000 km per day during migration. They are active during the day, with foraging activity influenced by tidal patterns.

All ruddy turnstone populations are migratory, traversing great distances across oceans and hemispheres to reach breeding and wintering grounds. It is estimated that there are 5 populations of ruddy turnstones worldwide. Most ruddy turnstones arrive on breeding grounds in May and June and depart for wintering grounds in late July through September, depending on latitude. They migrate in small, mixed-species flocks, often with red knots ( Calidris canutus ), semipalmated sandpipers ( Calidris pusilla ), sanderlings ( Calidris alba ), black turnstones ( Arenaria melanocephala ), surfbirds ( Aphriza virgata ), and dunlins ( Calidris alpina ), among others. Adults begin northward migrations before immature individuals. In the late summer and fall, failed breeders and females depart the breeding grounds first, followed by males and then fledglings. Individuals are thought to return to the general area where they hatched.

• Key Behaviors
• terricolous
• flies
• diurnal diurnal
• motile motile
• migratory migratory
• territorial territorial
• social social

Home Range

Ruddy turnstones vigorously defend breeding territories. The density of breeding pairs has been estimated at 1.6 to 4.5 pairs per kilometer. Territory sizes are from 800 square meters to 1500 hectares.

Communication and Perception

Ruddy turnstones use vocalizations and visual displays extensively in communicating with conspecifics. They use displays, both on the ground and in the air, to attract mates and reinforce pair bonds. Males vocalize more than females, but both sexes do produce a variety of calls in different contexts. Ruddy turnstones have been described as "noisy." Variations on a call that sounds like "kitititit" are contact and alarm calls. "Pri pri pri" type calls are used to call young. Clicking calls and sounds are used when distracting or attacking predators and high pitched "i i i" sounds are distress calls.

• Communication Channels
• visual visual
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

The ruddy turnstone diet varies seasonally between wintering and breeding habitats. They eat primarily invertebrates, mostly insects during the breeding season and crustaceans, mollusks, and other marine invertebrates during migration and winter. In the breeding season, ruddy turnstones use their stout bills to turn over rocks, probe through tundra vegetation or soils, and chase down mostly insect prey. Early in the season they may rely on carrion and plant materials, until insect prey becomes more abundant. Dominant prey in summer are flies and their larvae ( Diptera ), especially midges ( Chironomidae ), but also crane flies ( Tipulidae ), dance flies ( Empididae ), syrphid flies ( Syrphidae ), muscid flies ( Muscidae ), and blow flies ( Calliphoridae ). They also take spiders ( Dictynidae , Lycosidae , Linyphiidae , Thomisidae ), moth and butterfly larvae ( Lymantriidae , Liparidae , Noctuidae , Nymphalidae ), and beetles ( Coleoptera ). They may also take the eggs of colonial nesting birds ( Larus , Sterna ) in summer if they are nesting nearby. Once the young have hatched, families hunt together mostly along the margins of ponds and wetlands, where dipteran prey is most abundant.

In winter and during migration, ruddy turnstones take prey found on or just under the surface in their sandy, coastal habitats, especially crustaceans, mollusks, and polychaete worms. Diet varies with local and temporal availability of prey. During migration they will take advantage of highly abundant, but temporary, food resources, such as horseshoe crab eggs ( Limulus polyphemus ) on the mid-Atlantic coast during May and blowfly larvae ( Calliphoridae ) along the coasts of Alaska during August. Ruddy turnstones are opportunistic and will take carrion, the eggs of other birds, fish, and plant material as available. Dominant prey items in winter habitats include barnacles ( Balanus ), amphipods ( Gammarus , Caprella ), copepods ( Calanus ), shrimp and crabs ( Crago , Cancer , Hippa , Emerita , Carcinus , Eupagurus , Pagurus ), polychaete worms ( Nereis ), chitons ( Chaetopleura , Chiten ), periwinkles ( Littorina ), and bivalves ( Mytilus , Cardium , Mya ). They include other aquatic invertebrates in their diet as well.

Ruddy turnstones are aggressive birds, actively hunting down and efficiently manipulating prey. They use their stout bills to turn over rocks and other objects and probe into substrates to find prey. They are skilled at opening and dislodging bivalves and barnacles.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore

• Animal Foods
• fish
• eggs
• carrion carrion
• insects
• terrestrial non-insect arthropods
• mollusks
• terrestrial worms
• aquatic or marine worms
• aquatic crustaceans
• echinoderms
• other marine invertebrates

• Plant Foods
• fruit

Predation

Most predation on ruddy turnstones is on eggs and hatchlings. Known predators are long-tailed jaegers ( Stercorarius longicaudus ), parasitic jaegers ( Stercorarius parasiticus ), glaucous gulls ( Larus hyperboreus ), common ravens ( Corvus corax ), arctic foxes ( Vulpes lagopus ), and red foxes ( Vulpes vulpes ). Jaegers may be the primary predators, they will continue to visit nests that they discover until all eggs or young are taken. Predation pressure on ruddy turnstones and other shorebirds nesting in tundra is highest when population numbers of collared lemmings ( Dicrostonyx groenlandicus ) are lowest. Ruddy turnstones have dispersed nesting territories, even in habitats with dense populations, to make it more difficult for predators to discover nests. Males actively patrol the nesting territory and warn the female when there is a predator nearby. In response, females sneak away from the nest to disguise its location from the predator. When predators are detected by pairs with hatchlings, their warning calls cause the hatchlings to freeze and the parents may perform a distraction display, pretending to be injured. Adults are only occasionally preyed on, reported predators of adults are Eurasian sparrow-hawks ( Accipiter nisus ), peregrine falcons ( Falco peregrinus ), merlins ( Falco columbarius ), and owls ( Strigiformes ).

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Ruddy turnstones are important predators of insects and other invertebrates in their tundra breeding habitats and crustaceans and mollusks in coastal habitats at other times of the year. There are few parasites recorded in ruddy turnstones, only some records of nematode infections.

Economic Importance for Humans: Positive

Ruddy turnstones are interesting and charismatic members of coastal faunas throughout the world.

Economic Importance for Humans: Negative

There are no adverse effects of ruddy turnstones on humans.

Conservation Status

Ruddy turnstones are not considered threatened because of their large geographic range and population sizes. They are protected under the U.S. Migratory Bird Act. However, populations are threatened by many of the things that threaten shorebirds worldwide: alteration, destruction, and contamination of coastal habitats. Their breeding grounds may be influenced increasingly by global climate changes. Especially critical is the impact of coastal disturbance on ruddy turnstones during migration, especially important staging areas where historically superabundant food resources, such as horseshoe crab eggs ( Limulus polyphemus ) or herring eggs ( Clupea harengus ), were critical to body condition during the spring migration.

Other Comments

Ruddy turnstones are one of 2 species in the distinctive genus Arenaria , along with black turnstones ( Arenaria melanocephala ). Their relationships with other sandpipers are poorly understood. There are two recognized subspecies: A. i. interpres , which occurs throughout the range of ruddy turnstones, and A. i. morinella , which is found breeding in southeastern Alaska, across the Canadian arctic to Greenland, and winters in coastal South America and the Antilles.

Additional Links

Encyclopedia of Life

BioKIDS Critter Catalog

Contributors

Tanya Dewey (author), Animal Diversity Web.

References

Larsen, T. 1991. Antipredator behaviour and mating systems in waders: aggressive nest defence selects for monogamy. Animal Behavior , 41: 1057–1062.

Nettleship, D. 2000. Ruddy turnstone (Arenaria interpres). The Birds of North America Online , 537: 1-20. Accessed April 02, 2009 at http://bna.birds.cornell.edu/bna/species/537 .