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. They look similar in all seasons and males and females look alike. Ruddy turnstones have reddish-brown feathers on their back and wings. They have black and brown feathers on the head and mixed in with the reddish feathers on their backs. 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.
Ruddy turnstones breed far north in arctic tundra from Alaska, across Canada, Greenland, Scandinavia, and northern Siberia to the Bering Sea. In winter they are found along almost all of the coastlines of the world, including North, Central, and South America, Africa, Europe, Asia, Australia, and Pacific Ocean islands.
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. (Nettleship, 2000)
Ruddy turnstones form mated pairs that stay together over many years. Pairs meet again in the same breeding territory used the last year. Ruddy turnstones are fairly aggressive and will even attack their mates at first. Males and females both use flight displays to help attract their mates. Once they are back together, males and females stay within sight of each other until they start incubating the eggs.
Ruddy turnstones arrive on the breeding grounds in late May and early June and mate and begin to lay eggs within 7 to 10 days of their arrival. They create a nest scrape lined with leaves and lichen. Females lay 1 egg each day and usually lay 4 dark brown or olive splotched eggs. 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.
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 if there are predators nearby, 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 them 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.
The longest recorded lifespan for ruddy turnstones in the wild is 19.7 years. Average lifespan in Finland was estimated at 6 to 7 years.
Ruddy turnstones are social when they aren't breeding, 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. Ruddy turnstones can fly quickly for long distances, more than 1000 km per day during migration. All ruddy turnstone populations are migratory, traveling great distances across oceans and hemispheres to reach breeding and wintering grounds. Most ruddy turnstones arrive on breeding grounds in May and June and depart for wintering grounds in late July through September, depending on latitude.
Ruddy turnstones aggressively defend breeding territories that are from 800 square meters to 1500 hectares in size.
Ruddy turnstones use calls and visual displays when communicating with others. They display on the ground and in the air to attract mates. Males call more than females, but both sexes use calls of different kinds. 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.
The ruddy turnstone diet varies seasonally between wintering and breeding habitats. They eat mainly invertebrates, mostly insects, mostly flies and their larvae, during the breeding season and crustaceans, mollusks, and other marine invertebrates during migration and winter.
Ruddy turnstones actively hunt down and efficiently manipulate prey. They use their stout bills to turn over rocks and other objects and probe into sand and soil to find prey. They are skilled at opening and eating bivalves and barnacles.
Most predation on ruddy turnstones is on eggs and hatchlings. Predators include long-tailed jaegers, parasitic jaegers, glaucous gulls, common ravens, arctic foxes, and red foxes. Many predators take more ruddy turnstone eggs and young when numbers of collared lemmings are low. Ruddy turnstones place their nests far away from others, in order to avoid being found by predators. Males patrol the nesting territory and warn the female when there is a predator nearby. The female will then sneak away from the nest so that the predators can't find it. Parents warn their hatchlings to freeze when they see a predator and the parents may try to distract the predatory by pretending to have a broken wing. Adults are only occasionally preyed on by birds of prey, like Eurasian sparrow-hawks, peregrine falcons, merlins, and owls.
Ruddy turnstones are 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 no adverse effects of ruddy turnstones on humans.
Ruddy turnstones are fun to watch as they forage along beaches.
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 also be influenced by global climate change. Especially serious is the effect of coastal disturbance on ruddy turnstones during migration. They rely on places along their migration route where superabundant food resources, such as horseshoe crab eggs (Limulus polyphemus) or herring eggs (Clupea harengus), help them gain fat for the rest of their migration.
Tanya Dewey (author), Animal Diversity Web.
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.