Dunlin (Calidris alpina)

In flight, dunlins form tight flocks, which make a distinct rushing noise when turning in the air. This sound is thought to be the result of air vibrating their stiff flight feathers.

Description

Dunlins are more colourful than most other sandpipers. Their upper parts are chestnut-coloured with black wings, while their underparts are white. They have a large dark blotch located centrally on their belly. The bill is long, sturdy, and slightly curved at the tip. Like most birds, their plumage is more subdued in the winter.

Distribution

Dunlins breed along the western coast of coast of Hudson Bay and, unlike many birds, in the adjacent Keewatin District, NV. They also breed in the Mackenzie Delta, and possibly on some of the Arctic islands.

Ecology

Courtship occurs in flight; the male pursues the female with erratic movements and a twittering song. Dunlins nest on wet marshes or tide flats, where they locate a dry spot, create a depression, and line it with grass and crisp leaves.

They eat a wide variety of invertebrates, predominantly insects but also spiders, molluscs and worms. Seeds are sometimes eaten in the spring, and crustaceans form a common dietary element in winter and during migration. Dunlins feed by gleaning prey items from the ground, and by probing the soil with their bills. When foraging, they usually walk, but occasionally run along the ground.

Mixed-species flocks of shorebirds are common during spring and fall migrations, and dunlins are frequent members of such groups. Their compact flight formations are especially well coordinated, zig-zagging to allow them to evade aerial predators. Individual birds also dive underwater to escape predation. This species of shorebird is a fairly confident swimmer, and readily takes to the water if pursued.