Strong Neighbor-Stranger Discrimination in Song Sparrows

Song Sparrows (Melospiza melodia) have medium-sized song repertoires and have been the main example for the generalization that neighbor recognition is weaker in species with larger song repertoires. Three previous studies of the Song Sparrow have indicated that neighbor-stranger discrimination by song is weak or absent in this species. In contrast to the previous studies, we found that territorial male Song Sparrows readily discriminated between neighbors and strangers based on a single song type from each. This result is strong and unequivocal evidence of neighbor-stranger discrimination in this species. We also present evidence that stability of neighbor boundaries may be required to demonstrate neighbor-stranger discrimination.