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Ruddy Turnstone Life History


ShorelinesRuddy Turnstones breed along rocky coasts and in the tundra across the High Arctic. In North America they breed in sparsely vegetated tundra near marshes, streams, and ponds. During migration they stop along coastal rocky and sandy beaches, mudflats, and shorelines of freshwater lakes to refuel. On their wintering grounds they congregate along rocky shorelines, mudflats, deltas, and sandy beaches. Back to top


Aquatic invertebrates

Ruddy Turnstones feed primarily on adult and larval flies and midges during the breeding season. They uncover their prey by flipping over rocks, pebbles, shells, or seaweed with their stout, slightly upturned bills. They also eat spiders, beetles, bees, and wasps. During the nonbreeding season they have a more diverse diet, eating everything from small crustaceans, to mollusks, to bird eggs. If they come across an unattended gull or tern nest they readily break open the eggs and eat the contents. They also pick at dead fish and mammals that wash up on the shores in early summer when insects have yet to emerge.

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Nest Placement

GroundMale and female Ruddy Turnstones explore potential nest sites within the male’s territory. Both make small scrapes in the ground with their bodies, but the female chooses the nesting location. Once she finds a spot, she makes a scrape, typically at the edge of tundra vegetation near a wet area and out of the wind. At other times she makes a scrape on bare gravel or in sand barrens.

Nest Description

The female makes a scrape in the ground by twisting her body to and fro to form a small depression. She collects small pieces of the surrounding vegetation such as lichens or willows to line the bottom of the depression.

Nesting Facts

Clutch Size:2-5 eggs
Egg Length:1.4-1.8 in (3.5-4.6 cm)
Egg Width:1.0-1.2 in (2.5-3 cm)
Incubation Period:21-24 days
Egg Description:Olive-green or buff speckled with brown.
Condition at Hatching:Chicks hatch covered in down and are precocial, or capable of leaving the nest within a few hours.
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Ground ForagerRuddy Turnstones strut along beaches and rocky shorelines stopping occasionally to flip rocks, seaweed, or other debris with their stout slightly upturned bill to look for insects and small crustaceans hidden beneath. They are strong fliers and speed past making sharp turns like many other shorebirds. Pairs are monogamous and territorial on the breeding grounds, often returning to the same area to mate with the same individual year after year. Upon arrival they face each other with ruffled feathers while calling and spreading their tails. After the initial face off, the male flies with slow and steady wingbeats around the territory and lands with head pushed forward, back feathers ruffled, and tail spread. After the display he follows the female everywhere, rarely standing more than 30 feet from her. Soon after, they begin looking for a place to nest. Most females lay eggs within 7 days of their arrival on the breeding grounds. In order to do this, they need to eat as much as they can as soon as they arrive. The female does most of the incubating while the male stands guard nearby, incubating on occasion. After the chicks hatch, territorial boundaries break down and families move to areas with abundant insects. Eggs and young are vulnerable to predation by Long-tailed and Parasitic jaegers, Glaucous Gulls, and foxes. When parents sense an approaching predator the male flies at the intruder while alarm calling. Upon hearing the alarm calls the female walks away from the nest to mislead the predator, and takes flight once she is far enough away from the nest. Like other shorebirds, turnstones migrate in stages. The first to leave the breeding grounds are birds that did not successfully breed, followed by females, males, and finally juvenile birds hatched that year. During migration they congregate in large groups and fly in unison to feed along rocky coasts, estuaries, rocky beaches, and sandy beaches. Back to top


DecliningRuddy Turnstones are common and widespread, but their remote breeding grounds make it hard to estimate population trends, especially since numbers tend to fluctuate naturally from year to year. The North American breeding population was estimated at 267,000 in 1999; in 2006 it was 8% lower, at 245,000. A separate study estimated a 77% decline in the number of birds detected at Delaware Bay between 1988 and 2007. It has been reported that counts on the coast of North America declined substantially between the 1980s and 2011, indicating that the population size could be lower than the 2006 estimate. Ruddy Turnstones rate an 11 out of 20 on the Continental Concern Score and are not on the 2016 State of North America's Birds Watch List. However, they are listed as a species of high conservation concern by both the Western Hemisphere Shorebird Reserve Network and the U.S. Shorebird Conservation Plan. Threats to turnstones include habitat loss along their migratory pathways and on their nonbreeding winter grounds, changes to their food resources, and plastic pollution. Coastal areas are prime sites for development, but beach development can eliminate or reduce wintering and stopover habitat. Turnstones and other shorebirds also rely on key places to refuel during migration. Delaware Bay is one of those critical stopover sites. Migrating shorebirds refuel on horseshoe crab eggs that are laid on the beaches in Delaware Bay in the spring. Overfishing of horseshoe crabs for bait has decreased the number of eggs available for shorebirds, which can affect their ability to arrive on the breeding grounds well fed and ready to breed. Stricter regulations on horseshoe crab harvest have been put in place in many regions and populations are now stable in the Delaware Bay region, but in the New York and New England areas horseshoe crab populations are still declining. Plastic pollution can also impact shorebirds as they mistake tiny bits of plastic for food. Once ingested, plastic often gets stuck in their digestive system and can result in death. Consider helping out on a beach cleanup near you or the next time you visit the beach, bring a bag and pick up a bit of trash. Reducing the amount of plastic you use can also help reduce the amount of plastic waste that can make its way to ocean shores. Back to top


Andres, B. A., P. A. Smith, R. I. G. Morrison, C. L. Gratto-Trevor, S. C. Brown, and C. A. Friis (2012). Population estimates of North American shorebirds, 2012. Wader Study Group Bulletin 119:178–194.

Andres, B., R. Clay and C. Duncan. Shorebird species of conservation concern in the western hemisphere. Western Hemisphere Shorebird Reserve Network (2006). Available from

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Morrison, R. I. G., B. J. McCaffery, R. E. Gill, S. K. Skagen, S. L. Jones, G. W. Page, C. L. Gratto-Trevor, and B. A. Andres (2006). Population estimates of North American shorebirds, 2006. Wader Study Group Bulletin 111:67–85.

Nettleship, David N. (2000). Ruddy Turnstone (Arenaria interpres), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.

Niles, L. J., J. Bart, H. P. Sitters, A. D. Dey, K. E. Clark, P. W. Atkinson, A. J. Baker, K. A. Bennett, K. S. Kalasz, N. A. Clark, J. Clark, S. Gillings, A. S. Gates, P. M. Gonzalez, D. E. Hernández, C. D. T. Minton, R. I. G. Morrison, R. R. Porter, R. K. Ross and C. R. Veitch. (2009). Effects of horseshoe crab harvest in Delaware Bay on Red Knots: Are harvest restrictions working? BioScience 59 (2):153-164.

Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.

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