Curlew Sandpiper Calidris ferruginea Scientific name definitions

Most adult Curlew Sandpipers acquire their rufescent breeding garb before embarking on their northbound migration so that they are properly attired to attract a mate, which most successfully do as they head northwards. The nonbreeding grounds from which they depart are extensive, stretching from western and southern Africa, east through India, to Australia and New Zealand. The breeding areas in the Siberian high Arctic to which they are headed are much less expansive, extending from 71°40' E on the Yamal Peninsula east to Dzhenretlen Cape at 174°19' W on the Chukotka Peninsula. Notably, Curlew Sandpipers are rather faithful to their wintering sites and are somewhat so to migration stopover sites, but they are seemingly little tied to specific breeding locations. Indeed, the species appears to use an "all-to-all" migration strategy, with no specific links between portions of the breeding and wintering ranges, which may well be why there is no geographic variation.

The Curlew Sandpiper does seem to prefer the typically clement climate of its wintering grounds over the oft tempestuous weather of its breeding areas. They often arrive in the Siberian high-Arctic just as the winter ice and snow are melting away, ready to nest, and they do not dawdle. The first egg is often laid within 5–6 days of arrival, and the (usually) four-egg clutch is completed about three days later. The male, his job completed, then departs for points south. The female incubates the eggs for approximately 20 days, and the chicks that emerge are then tended to until they are independent, some 14–20 days thereafter. The female then heads south as well, leaving the young to fend for themselves as they fatten up for their first migration. All going well, approximately one month later, Curlew Sandpiper juveniles also say farewell to the Arctic, making their way southwards. These young birds do not head back to the Arctic to breed during their first year, but rather they largely stay at or near their nonbreeding locations through the Austral winter, the only time during their lives that they will actually experience winter on the wintering grounds.

In the Arctic, this species favors tundra with an abundance of boggy depressions and pools, avoiding barren areas as well as places with tall or dense vegetation. During migration and the nonbreeding season, it mostly inhabits coastal mudflats, saltpans, sewage ponds, and rice paddies. In these habitats, it hunts small invertebrates, largely by jabbing, probing and gleaning, though at times the seeds of some marsh plants, such as Salicornia, are eaten. Away from the breeding grounds, the Curlew Sandpiper is often found in large flocks, often containing multiple shorebird species.

Despite its proportionately small breeding range, the Curlew Sandpiper has traditionally been one of the more common shorebirds throughout much of its migratory and wintering range, and the Curlew Sandpiper's population was estimated in 2015 at 1,085,000–1,285,000 individuals. However, the population along the East Asian-Australasian Flyway declined at circa 7.5% per year from 1993–2012, with an apparent corresponding decline of 82% in Australia between the early 1980s and late 2000s. This is likely due, at least in part, to severe degradation of shorebird habitat along the Yellow Sea, which provides the most important staging areas used by shorebirds along the East Asian-Australasian Flyway. However, severe local declines have also been noted at major wintering sites in India. Because of these alarming numbers, the Curlew Sandpiper is now considered Near Threatened by the IUCN.