Curlew sandpiper

Voice

A soft, rippling, two-syllable chirrup, clearly fuller and more musical than the rasping kreeep of Dunlin. Often that call is the only thing that betrays a Curlew Sandpiper in a mixed flock. Heard on autumn passage from July to September, and briefly in May during the spring movement.

Identification

Slim and long-legged, with a long, evenly decurved bill and a clear white supercilium. Breeding adults are brick-red from the face right down to the lower belly; in winter they are pale grey above and white below. Juveniles, by far the commonest here, have neatly scaled upperparts and a warm peach-buff breast. In flight the square white rump above the narrow wingbar is decisive.

Confusion species

Dunlin is shorter in leg and bill, with a kink near the tip rather than a smooth curve, and always shows a dark central stripe down the rump. Sanderling is shorter-billed, far whiter and has a black shoulder patch. If in doubt, wait for the birds to fly: only Curlew Sandpiper shows an entirely white, square rump.

Habitat

Shallow brackish pools and soft mud edges, where it wades deeper than Dunlin and probes to the base of the bill. On passage it uses coastal borrow pits, flooded fields, restored wetlands and the margins of saltmarsh creeks. It breeds on wet, sedge-covered tundra along the Siberian Arctic coast.

Range and movements

Breeds only on the Siberian tundra, from the Yamal peninsula to the Kolyma, and therefore nowhere in Europe. The Netherlands lies on the flyway to West Africa: adults pass in July and August, juveniles in August and September, chiefly in the Delta and along the Wadden coast. In Spain it is a valued passage migrant in the Ebro delta and Doñana.

• Resident
• Breeding (summer)
• Winter
• Passage
• Migration direction
• dark = core range, pale = thinly spread

Where and when to look

The best window is the second half of August, at coastal borrow pits and shallow brackish pools in Zeeland or along the Wadden coast. Come around high water, when birds move off the flats to pools behind the dyke. Work through the Dunlin flocks methodically and watch for the longer legs and fine white supercilium; the bird stands just above the rest.

Conservation status

The species is listed as Near Threatened and is declining along most flyways. Breeding success swings sharply with the lemming cycle on the tundra, and warm, snow-poor summers disrupt that rhythm. Along the route to West Africa coastal wetlands are lost to land claim, salt extraction and disturbance, while waders are still hunted in parts of the flyway.