The white-rumped sandpiper is a migratory bird, and performs one of the longest animal migrations in the western hemisphere (2) (3). It typically travels from its principal breeding ground in the Canadian Arctic to the southern-most countries of South America (2) (3). This migration is undertaken in stages of up to 4000 kilometres (2) (4). It depends on feeding heavily during migration stopovers in order to build up enough body fat to survive these long flights, which can last up to 60 hours (2).
The white-rumped sandpiper feeds mainly on invertebrate prey, such as insects, molluscs and worms, but is also known to feed on plant material. It feeds by probing with its bill into vegetation, mudflats, or shallow water, depending on its location (2) (3). It has been observed making several quick probes with its bill, before running a short distance and repeating this action (2). It has also been seen to snatch food from the surface of mud or water if it is available (2) (3). The white-rumped sandpiper may defend feeding territories, but will forage in small groups (2).
The white-rumped sandpiper is swift when flying, and walks or runs instead of hopping when on the ground. It flies in small groups, and has been recorded reaching speeds of up to 80 kilometres per hour (2).
Male white-rumped sandpipers vigorously defend breeding territories while females are laying eggs, but abandon them soon afterwards. It is a polygynous species, and it is thought that the quality of the male’s breeding territory may attract females to breed. Male white-rumped sandpipers perform short, aerial courtship displays to the females. These involve hovering around 10 to 25 metres in the air while calling out a distinctive song involving ‘rattling’ and ‘pig-like’ sounds. Breeding males extend their throat during aerial displays. Throughout the breeding season, males have larger throats than females and, consequently, this is one of the only times when it is possible to distinguish between the sexes (2).
Female white-rumped sandpipers construct their nests without the assistance of males, and the nests are typically only just wide enough to fit four eggs inside. The nests are often generously lined with vegetation, which is thought to fall in naturally rather than being placed there intentionally by the female. White-rumped sandpiper eggs are oval, usually between 26 and 31 millimetres in length and green in colour with reddish-brown spots and blotches. Incubation and care of the chicks is also undertaken solely by the female. White-rumped sandpiper chicks are able to fledge from 16 to 17 days old, and are extremely independent as soon as they have left the nest (2).