Least Sandpiper (Calidris minutilla) is the smallest shorebird. Their breeding habitat is the northern North American continent on tundra or in bogs. They migrate in flocks to the southern United States and northern South America.
The Sanderling, Calidris alba, is a small wader. It is a circumpolar Arctic breeder, and a long-distance migrant. Winter: Coasts from S AK & Nova Scotia south to S Chile & AR. Found on almost all temperate & tropical marine beaches throughout the world
Curlew Sandpiper (Calidris ferruginea) is a small wader that breeds on the tundra of Arctic Siberia. It is strongly migratory, wintering mainly in Africa, but also in south and southeast Asia and in Australasia. It is a vagrant to North America.