This paper describes the system of local dialects in the Corn Bunting in Britain. Each dialect population contains between 30 and 100 males, all males within a dialect sing the same form and number of song types. The Corn Bunting is therefore the first species for which both clear local dialects and a repertoire of song types have been described. The boundaries between dialects have remained in the same position for three years. The origin, maintenance and functional significance of dialects in this species are discussed.