Body length: 30 cm. Wingspan: 58 cm. Plumage: has seasonal and age dimorphism. Adults: during breeding season the head and neck are black, back and wings – black-brownish, the hindneck feathers slightly elongated, on and above ear-coverts a fan of golden-yellow feathers, the loins rusty and the belly silky-white. The bill slightly uptilted. At end of breeding season the loins lose colour, and the sides of the head have rusty-brown feathers. In autumn and winter upperparts are grey-brown and the underparts grey-white. Juveniles resemble the adults in winter, but with a darker neck. Voice: during breeding season "tseepee", “wip" and high-pitched trills. Biotope: different-sized fresh water basins with reed beds and dense under-water vegetation. During migration and wintering in groups in diverse wetland areas, mainly seashores.