Small, slender wader adapted to living on the surfaced of water. Circumpolar breeder found on coastal and inland tundra in Arctic, forest and alpine zones, always near lakes, pools or other water, solitary or in loose colonies. Outside the breeding season is in flocks of up to 200 individuals, occasionally more. Eats insects and other small invertebrates during the breeding season, otherwise takes larval brine-flies from saline lakes, and zooplankton when feeding pelagically. Long-distance migrant spending most of winter on the open sea in the northern tropic region.