Individual recognition by song in white-throated sparrows. I. Discrimination of songs of neighbors and strangers

Abstract
Playback of recorded songs of white-throated sparrows (Zonotrichia albicollis) to territorial males elicited a stronger response to songs of strangers than to songs of territorial neighbors. Responses to a bird's own song were intermediate. All test songs were played on the territorial boundary adjacent to the neighbor used in the experiment. Peak of response by song occurred in the 1st min after cessation of playback.Two sets of experiments, 3 weeks apart, showed waning of response to neighbors' songs, but no change in response to strangers' songs. This waning progressed steadily over a 6-week period. No decrement was observed when four periods of playback of a neighbor's song were presented within 1 h. Response to a neighbor's song within a 1-h sequence was independent of whether the preceding playback was of a stranger or neighbor. This indicated that discrimination occurred after only one or two renditions of a song.The mechanism of differential response is interpreted as habituation to neighbors' songs. Adaptiveness of this behavior is discussed.