Sparrow-sized but slim and with a long, deeply notched tail, the male has a black head, white collar and a drooping moustache. Females and winter males have a streaked head. In flight the tail looks black with broad, white edge
Predominantly a farmland and wetland bird. Typically found in wet vegetation but has recently spread into farmland and, in winter, into gardens. When singing the male usually perched on top of a bush, or reed.