Effect of androgens on structure and rate of growing in the Japanese quail(Coturnix Japonica)

To study the influence of testosterone (T) on crowing in male Japanese quai ls, we combined hormonal and photoperiod manipulations of circulating andro gens with a detailed analysis of the acoustic parameters of crows and of ma le courtship patterns. The structure of crowing was directly affected by T: high-androgen males uttered longer and lower-pitched calls than the others , call rate at dawn being related to androgens by a minimum threshold funct ion. High- and low-callers, two consistent categories over many days, diffe red in their sexual performance: high-callers performed more courtship than low-callers, but there was no difference in attempted mating. Growing is d iscussed as a potential target of sexual selection because, like a song, it is androgen-dependent, highly variable among individuals, and plastic in i ts structure at the beginning of the reproductive season.