Dunlin, Calidris alpina
Dunlin, Calidris alpina. Photograph taken on the beach in Longboat Key, Florida, January 2020.
Dunlin, Calidris alpina. Photographs taken on the beach in the greater Fort Lauderdale, Florida, January 2023. Photographs and identification courtesy of Faith Hubsch, Fort Lauderdale, Florida.
Background and Identification
The Dunlin, Calidris alpina, is a member of the Scolopacidae Family of Sandpipers and Allies. This species is a small to medium-sized shorebird known for its distinctive breeding and non-breeding plumages. They primarily consume mollusks and polychaete worms on the beaches they frequent. In Mexico, they are known as Correlimos Común.
Dunlins are a medium-sized sandpiper, with an average length of 16 cm (6.3 inches) to 22 cm (8.7 inches). The average mass for both sexes is 48 g (1.69 oz) to 64 g (2.26 oz). During the breeding season, the Dunlin exhibits a striking combination of reddish-brown upperparts, a black patch on its belly, and a slightly downcurved black bill. In non-breeding plumage, they become much duller, with grayish-brown upperparts and a white belly. They have long legs and a relatively short neck. Their bill is slightly longer than their head, and the downward curve helps differentiate them from other small sandpipers. In flight, Dunlins show a characteristic white wing stripe. Their calls are high-pitched and somewhat buzzy, often heard during migration or on their breeding grounds.
Habitat and Geographical Range
Dunlins are found resting on sandbars and beaches in coastal areas protected from open surf including bays, ocean beaches, estuaries, and tidewater flats.
Dunlins are highly migratory, with a wide geographical range that spans the Northern Hemisphere. During the breeding season, they are found in Arctic and subarctic regions, nesting in wet tundra habitats. They are particularly associated with coastal areas of Alaska, Canada, Scandinavia, and Russia during this time. In the non-breeding season, Dunlins migrate to coastal wetlands, estuaries, and mudflats in temperate and subtropical regions. Wintering grounds extend along the coasts of North America, Europe, Asia, and parts of Africa. In North America, they are commonly seen along both the Atlantic and Pacific coasts during the winter, foraging in large flocks in mudflats and marshes. In Mexico they are found in the coastal regions within the Atlantic Slope in the States of Tamaulipas and Veracruz, and within the Pacific Slope in the States of Baja California, Baja California Sur, Sonora, and Sinaloa at low elevations.
Common Misidentifications
Dunlins are often confused with other small sandpipers, especially during migration when they mix with similar species. One common misidentification is with the Western Sandpiper, Calidris mauri, which also has a slightly downcurved bill. However, Dunlins are larger, have longer bills, and in breeding plumage, the distinctive black belly patch makes them easy to distinguish.
Conservation Status
From a conservation perspective the Dunlin is currently considered to be of Least Concern. However, their overall populations are decreasing. In many coastal areas, their population decline is due to habitat loss. They depend on mudflats and estuaries for foraging during migration and winter. Wetland degradation, climate change, and human disturbance are the primary threats to Dunlin populations. Conservation efforts focus on protecting key coastal habitats and ensuring the availability of stopover sites during migration.