Song repertoire development in male cowbirds (Molothrus ater): its relation to female assessment of song potency.

Two studies were conducted to investigate the relation between the male cowbird's (Molothrus ater ater) development of a song repertoire and the female cowbird's assessment of song potency. Male development was assayed by vocal copying and female assessment by copulatory responsiveness to song playback. The results demonstrate that males do not copy most often the particular songs that females respond to most often. Whereas rank orderings of potency were highly correlated across two independent samples of playback females, male and female rank orderings were not significantly correlated. The data highlight the potential significance of social interactions between and across the sexes for repertoire development.