Ecological correlates of song learning in song sparrows

Abstract

Most studies of song learning have been conducted in the laboratory, and thus little is known about how song learning is affected by ecological variables in nature. Taking an ecological perspective, we studied song learning and territory establishment in a sedentary population of song sparrows (Melospiza melodia). We examined the song repertoires of an entire cohort of males (41 subjects) hatched in 1992 and compared them to those of potential song tutors (adults who were present in the young birds’ first year). We found that a young bird learns songs from multiple tutors who were neighbors in his first year and usually establishes a territory among or near these tutors. The degree to which tutors influenced the repertoires of the young birds varied greatly. Adult males who survived into 1993 tutored more songs than those who did not survive, supporting the hypothesis that a young male’s repertoire is influenced by social interactions with adults continuing beyond the classical sensitive period of the natal summer. The final repertoire of a young bird in most cases was weighted toward one of his tutors with whom he continued to interact, as an immediate neighbor, into his first spring. We found no correlations between potential measures of male quality or vigor and degree of tutor influence.