Sanderling (Calidris alba)

[order] CHARADRIIFORMES | [family] Scolopacidae | [latin] Calidris alba | [UK] Sanderling | [FR] Becasseau sanderling | [DE] Sanderling | [ES] Correlimos tridactilo | [NL] Drieteenstrandloper

Subspecies

Physical charateristics

The Sanderling is a small, light-colored sandpiper with a straight, black bill and black legs. The male and female look similar. In breeding plumage, it has a rufous head and neck and a rufous wash that extends onto its back. In non-breeding plumage, the adult is white underneath and very pale gray above while the juveniles are white underneath with a dark and light mottled top. Late-molters, Sanderlings don’t reach their breeding plumage until late May. This is the only sandpiper that lacks a hind toe, which allows it to be a strong runner.
Sanderlings flock, and members of different flocks interchange freely. The quintessential surf-dodger, the Sanderling is most recognized for its behavior of running down to the water’s edge with an outgoing wave, and racing back up the beach to avoid the next incoming wave. Dunlins and Western Sandpipers also do this, so this behavior is not diagnostic. They feed by probing, and leave bands of holes along a beach where they have stuck their beaks into the sand probing for food. They also feed in tire tracks. When roosting, they usually stand on one leg, and if disturbed, they will hop away from the disturbance on one leg.

Listen to the sound of Sanderling

[audio:http://www.aviflevoland.nl/sounddb/S/Sanderling.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

North America, Eurasia : North

Habitat

Sanderlings breed farther north than any of the shorebirds found in Washington, nesting in dry, rocky tundra on the land closest to the North Pole. In winter and during migration, they inhabit broad, coastal beaches with light-colored sand. They can also be found on gravelly and rocky beaches and mudflats, and on top of kelp beds. In the fall, adults dominate the optimal habitats, and juveniles take the remaining spots.

Reproduction

Sanderlings nest on the dry, northern tundra, often close to lakes or ponds. The nest is on the ground, often on an elevated spot out in the open. The nest is a shallow scrape lined with leaves. The female generally lays two clutches, and either two males, or one male and the female herself, each incubate a clutch of four eggs. If the female has two males incubating the eggs, she will depart. If she is incubating a clutch, she will stay with the young, which hatch after 24 to 31 days, until they fledge at about 17 days. Males also stay with the young, which leave the nest and can feed themselves immediately after hatching.

Feeding habits

Sanderlings dine on a variety of aquatic invertebrates and sometimes carrion. One study identified young razor clams as a major source of food on the Washington coast.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Migration

Long distance migrant. Seems to be restricted to few stopover sites along flyways. Highly faithful to wintering sites. Migration largely offshore and coastal, but locally frequent inland across Africa and North America. Also occurs on many small oceanic islands. Birds from Greenland and Siberia pass through British Islands, some staying there, but most winter down continental coasts from Europe South to South Africa. Evidently loop migration, as in spring some birds from West Africa cross Sahara to Central Mediterranean. Siberian birds East of Taymyr move down East Russian coast or overland, to Indian Ocean and South West Pacific; in East Asia, common migrant through Korea, East China and Japan, and also through Vietnam and Cambodia. Birds wintering in South East Asia and Australia probably originate from New Siberian Islands. Nearctic birds move along Pacific and Atlantic coasts and via prairies and Texas coast. Most abundant on Pacific coast of South America, whence N orth migration mainly via inland and Atlantic routes. High numbers staging at Delaware Bay, probably mostly from Brazil. Pacific North American winterers migrate along Pacific coast. Many 1-year-olds apparently return to breeding grounds, but some remain South all year.

Distribution map