Response of male song and swamp sparrows to neighbour, stranger, and self songs

In 2-speaker tests, male swamp sparrows Melospiza georgiana failed to discriminate between neighbor and stranger songs and between self and stranger songs. In single speaker presentations, male swamp sparrows responded more aggressively to stranger song than to neighbor song and gave intermediate responses to self song. Male song sparrows M. melodia showed no significant discrimination between neighbor, stranger and self songs. Male birds may learn what other conspecific songs should sound like by listening to their own songs. This hypothesis might predict maximal responsiveness to playback of a male's own song, a prediction not here verified. That there was less of a difference in responsiveness toward neighbor and stranger songs in song sparrows than in swamp sparrows is compatible with the hypothesis that larger repertoires make neighbor recognition more difficult.-from Authors