Repertoire matching occurs when one songbird replies to another with a song type that the two birds share. Repertoire matching has previously been demonstrated to occur at well above chance levels in a western population of song sparrows, where it is hypothesized to serve as a low level threat in a hierarchy of aggressive signals. Here we test for repertoire matching in an eastern population of song sparrows. Previous work indicates that this eastern population differs from the western one in having lower levels of song sharing between neighboring males and in showing no association between song sharing and territory tenure. Here we confirm that males in this eastern population on average share few whole songs with their neighbors. The eastern males are familiar with their neighbors’ repertoires, as evidenced by a stronger singing response to stranger song than to neighbor song. Males in the eastern population did not repertoire match: when played an unshared song type from a specific neighbor, they did not reply with a song type shared with that neighbor more often than expected by chance or more often than in response to playback of a control song (an unshared stranger song). The results thus demonstrate a qualitative difference in vocal signaling strategies between two populations of the same species.

Sharing Analysis 2013-14Data on the sharing metric for whole song sharing and introductory phrase sharing. For each male (identified by color band combination) the sharing metric is averaged across his adjacent neighbors. Also given are song repertoire sizes and number of songs recorded.Song sharing per dyad of adjacent male song sparrowsFor each pair of adjacent territorial male song sparrows, the file gives the number of whole song types shared and the number of introductory phrases shared.Dyad analysis.xlsxPARTIAL MATCHING ANALYSISFor each focal male, whether he did (YES) or did not (NO) repertoire match playback of an unshared neighbor song and whether he sang the same target song(s) for playback of an unshared stranger song, counting partially shared songs as a repertoire match.WHOLE SONG MATCHING ANALYSISFor each focal male, whether he did (YES) or did not (NO) repertoire match playback of an unshared neighbor song and whether he sang the same target song(s) for playback of an unshared stranger song, counting only wholly shared songs as a repertoire match.neighbor:strangerNumber of songs given by subjects in response to playback of neighbor song and to playback of stranger song.