A European robin-sized bird, the dunnock typically measures 13.5–14 cm (5.3–5.5 in) in length. It possesses a streaked back, somewhat resembling a small house sparrow. Like that species, the dunnock has a drab appearance which may have evolved to avoid predation. It is brownish underneath, and has a fine pointed bill. Adults have a grey head, and both sexes are similarly coloured. Unlike any similar sized small brown bird, Dunnocks exhibit frequent wing flicking, especially when engaged in territorial disputes or when competing for mating rights. The main call of the dunnock is a shrill, persistent tseep along with a high trilling note, which betrays the bird's otherwise inconspicuous presence. The song is rapid, thin and tinkling, a sweet warble which can be confused with that of the Eurasian wren, but is shorter and weaker.