The Surfbird is a species of the Pacific Coast of the Americas. It breeds in isolated alpine tundra sites in Alaska and a small area of the Yukon Territory in Canada. From there it spreads south to much of the Pacific Coast from Alaska to south-central Chile in the non-breeding season. Its habitat is specifically rocky coasts, usually in colder water regions. It is most common along the coast of the US to Mexico, and then becomes much less abundant through Central America and northern South America before increasing in abundance again in Peru and Chile. In the northern hemisphere it shares this non-breeding habitat with the Black Turnstone (Arenaria melanocephala) while in the southern hemisphere it is found with the Ruddy Turnstone (Arenaria interpres). The relationships of the Surfbird have been up until recently unclear, and that is underscored by its placement in a single species genus. However molecular data strongly suggests that the two species of knot are the closest relatives of the Surfbird, and some aspects of plumage support this assertion. It seems logical that the Surfbird should therefore be moved to the genus Calidris, or a genus be erected for the Knot-Surfbird group, but keeping the Surfbird in its own genus does not appear tenable given what we know now.