Sandpipers and Allies
Calidris alpina
The Dunlin is a small, migratory shorebird found across the Northern Hemisphere. It exhibits a striking plumage transformation between its breeding and non-breeding seasons, making it appear as two different birds. Outside of the breeding season, it often gathers in large, cohesive flocks along coastal mudflats and estuaries.
Typical adult measurements.
Individuals and populations vary.
01 / The telltale details
Start with shape and behavior. Then look for the smaller details.
Vivid rusty back and crown, with a prominent black belly patch contrasting with white underparts.
Dull grayish-brown upperparts, head, and breast, with pale underparts.
A sturdy, medium-long black bill with a noticeable downward curve at the tip.
Moderately long, black legs are consistent in all plumages.
02 / A place in the world
Dunlin breed in wet tundra environments, often near small ponds and hummocks. During migration and winter, they favor coastal habitats such as mudflats, estuaries, and sandy beaches, but can also be found in flooded fields and lake shores.
This species has a circumpolar breeding range across the Arctic and subarctic. In winter, Dunlin migrate to coastal and inland wetlands in temperate to tropical zones, primarily north of the Equator, including North America, Europe, Africa, and Asia.
Dunlin are migratory, with some populations undertaking short-distance movements and others long-distance migrations. Birds breeding in northern Alaska, for example, may migrate westward to winter in Asia, while others move along North American coasts.
03 / Listen a little closer
Males perform a trilling song during display flights over their breeding territories.
04 / The life behind the feathers
Their diet primarily consists of invertebrates. On breeding grounds, they consume insects like midges and beetles. Along coasts, they eat marine worms, small mollusks, crustaceans, and occasionally small fish, as well as some plant matter.
Dunlin forage by picking items from the surface or by probing into mud or fine sand with their sensitive bill tips. They often use a rapid 'stitching' motion, probing multiple times per second, and can feed day or night.
Nests are shallow scrapes on the ground, typically well-hidden within grass clumps or hummocks. Both sexes contribute to creating scrapes, but the female selects one and lines it with leaves and grass. They usually lay four eggs.
Outside of the breeding season, Dunlin are highly gregarious, forming large flocks that can perform synchronized aerial maneuvers. During breeding, males display with fluttering, gliding flights and defend territories, though they may feed peacefully with other males outside their territory.
One more reason to pay attention
The Dunlin was formerly known as the Red-backed Sandpiper due to its striking breeding plumage.
Dunlin are among the hardiest shorebirds, wintering farther north than many other species.
Some Dunlin breeding in northern Alaska migrate across the Pacific to winter in Japan and China.
05 / An eye for the difference
Western Sandpipers are generally paler, especially on the chest, and are smaller than Dunlin.
Purple Sandpipers are typically darker, chunkier, and have paler legs compared to Dunlin.
Rock Sandpipers are darker and chunkier with paler legs; in western Alaska, they can be confused with breeding Dunlin.
AI-assisted species research. Prepared September 2026. Details can vary across regions and populations.