The great knot is a small wader. It is the largest of the calidrid species. The genus name is from Ancient Greek kalidris or skalidris, a term used by Aristotle for some grey-coloured waterside birds. Their breeding habitat is tundra in northeast Siberia. They nest on the ground laying about four eggs in a ground scrape. They are strongly migratory wintering on coasts in southern Asia through to Australia. This species forms enormous flocks in winter. The species is recorded in low numbers in western Alaska most years, and has occurred as a vagrant in British Columbia, Oregon, West Virginia, and Maine. These birds forage on mudflats and beaches, probing or picking up food by sight. They mainly eat molluscs and insects. This species has short dark legs and a medium-length thin dark bill. Breeding adults have mottled greyish upperparts with some rufous feathering. The face, throat and breast are heavily spotted black, and there are also some streaks on the rear belly. In winter the plumage becomes uniformly pale grey above. This species is classified as Endangered by IUCN.