White-rumped Sandpiper (Calidris fuscicollis)
The white-rumped sandpiper is a member of the small group of Calidris sandpipers known as ‘peeps’. It is 18-20 cm long, a little smaller than a cardinal. These sandpipers are small shorebirds that change their colours from greys and browns in winter to darker brown and rusty in the breeding season. They can be distinguished from other peeps by their heavily streaked breasts and, in flight, their completely white rumps. Males and females are similar in size and weight.
The white-rumped sandpiper is a central Arctic species, breeding in Canada from the Arctic coastline northwards, and absent only from Ellesmere Island and other northernmost parts of the High Arctic.
In the breeding season, it hollows out a nest on the tundra and lines it with dry grass. Occasionally the female lays two separate clutches of eggs, incubating and rearing one brood of young herself, while her mate incubates and cares for the other.
The white-rumped sandpiper preys mainly on insects, spiders, and aquatic invertebrates, but also eats some plant matter. It obtains food by gleaning, or picking food from the ground, and by methodically probing the soil with its bill. Occasionally, these birds may forage in water that is belly-deep, submerging their heads entirely!
In fall and winter, they sometimes defend feeding territories, protecting an area of shoreline where there is a good food supply. The white-rumped sandpiper may be seen migrating and feeding with pectoral sandpipers or Baird's sandpipers.