Semipalmated sandpiper

Voice

A low, short, slightly hoarse chert or chirrup, sometimes given twice, fuller and lower than the dry tit of Little Stint and without the piercing quality of Western Sandpiper's jeet. In a mixed flock lifting off a pool that low note is often the first thing that stops you. On the breeding grounds displaying males give a pulsing, motorboat-like vurra-vurra-vurra followed by twittering phrases that sound like sped-up call notes; in Europe only the flight call is on offer.

Identification

Small and compact, with a short, straight, deep-based bill ending in a distinctly blunt tip; eastern females are longer-billed and can show a slight droop. Legs black, with small webs between the front toes. Breeding adults are dull grey-brown with dark feather centres and at most a hint of rust on crown and ear-coverts, lacking the warm tones of the other peeps. Juveniles look evenly grey-brown and scaly with pale buff fringes, a dark cap, a dark loral line and only a faint mantle line. Winter birds are plain grey with a greyish breast-side patch. The wing tips reach the tail tip, and the tertials cloak most of the primaries.

Confusion species

Against Western Sandpiper the bill decides: short, straight and blunt-tipped rather than long, deep-based and drooping at the tip, and no rufous scapulars in any plumage. Both species show the toe webs the bird is named for, best seen on a bird wading a shallow film of water or in the moment before it lifts; Least Sandpiper and Red-necked Stint lack them. Least Sandpiper also has yellow-green legs, a finer and slightly decurved bill, browner and more heavily streaked plumage and a complete streaked breast band. Red-necked Stint is shorter-billed and longer-winged, with primaries projecting beyond the tail and an attenuated rear end, and in summer shows a clean brick-red throat bordered by a necklace of streaks where Semipalmated keeps a densely streaked breast band. The real work, though, is against Little Stint, the species you are combing through on every east coast pool: Little Stint is finer-billed with a pointed tip, has no toe webs, shows bright white mantle braces and a split supercilium as a juvenile, and carries black-centred scapulars with rufous fringes where Semipalmated has paler buff fringes and a capped, plainer face. Temminck's Stint barely enters the argument with its yellow-olive legs, even grey breast cut sharply against white and white outer tail feathers. Dunlin is settled on size and the longer, decurved bill.

Habitat

In Britain and Ireland typically on sandy beaches and estuary edges among Sanderling and Dunlin, and on coastal lagoons, saline pools and the drying margins of reservoirs and sewage works. Feeds by pecking and shallow probing in the top few millimetres of mud, usually within a fast-moving party of small waders. Breeds on wet sedge tundra and boggy coastal plains across arctic North America from Alaska to Labrador.

Range and movements

Breeds across arctic North America and winters on the coasts of Central and South America, with the Guianas holding the bulk of the population. In Britain and Ireland it is the commonest Nearctic peep, still assessed as a rarity but found in increasing numbers each autumn; the classic arrival window opens around 20 August with a peak in mid to late September, and western Ireland and the Outer Hebrides produce a disproportionate share. Elsewhere in the region it is much thinner: fifteen accepted Dutch records between 1989 and 2023, nearly all adults, with the first juvenile only in September 2024, and around eight Spanish records, five of them in Galicia.

Where and when to look

Work sandy shores and estuary strandlines in the second half of September, concentrating on Sanderling flocks rather than only on the pools, and on the south-west Irish sites that already gather Nearctic waders, from Tacumshin and Ballycotton to the Shannon estuary. Approach low along the tideline so the flock feeds towards you, then take every stint in turn on bill tip and leg colour before looking for the toe webs. An adult in worn plumage in early autumn is as likely as a juvenile, so do not filter for fresh-plumaged birds.

Conservation status

Near Threatened. The eastern population has fallen sharply, most clearly documented by counts on the wintering grounds in the Guianas, which recorded dramatic declines. Shorebird hunting in the coastal wetlands of Surinam, disturbance and loss of staging sites along the Atlantic seaboard, and shifting food supplies on intertidal flats are the main pressures. In the Bay of Fundy the autumn passage of nearly the whole population passes through a handful of mudflats, which leaves little margin.