The mimicry of male superb lyrebirds is a well-known example of a sexually selected trait. Females prefer males that produce more accurate mimicry and that have a greater diversity of mimetic songs in their repertoire. Although to the human ear the differences between songs are indistinguishable, there are differences in the mimetic song quality between individual lyrebirds due to signal degradation, reverberation and attenuation, as well as the frequency and volume attained. There is evidence that there are costs associated with the development of mimetic song, and while these costs are currently unknown, they indicate that that quality of a lyrebird's mimetic song is an honest signal that can be used by females in mate selection.