Sexes alike. Black and white plumage, long, bluish legs and long, slender upcurved beak diagnostic. In flight, the long legs extend much beyond the tail. Usually gregarious, only sometimes 2 to 3 birds scattered over waterbody; frequently enters shallow water; characteristic sideways movement of head when
feeding, the head bent low as upcurved beak sweeps along bottom mud; also swims and up-ends, duck-like.