Adult and peer influences on starling song development.

Adult influence on song development was rarely investigated in complex social settings. We investigated the influence of the young/adult ratio on song learning in European starlings. Starling songs are composed of two categories: whistles and warbling. Warbling includes three parts: complex variable motifs, click motifs, and high frequency motifs. Song learning by young birds raised in group (G birds), in group with adults (GT birds) or in pair with one adult (IT birds) were compared. Song tutor choice, song sharing, and song quality varied with social context. The mere presence of adults in a group was not sufficient for young to develop all adult song features. Only IT birds chose adults as tutors. Social contact with only one adult enhanced acquisition of whistles, click motifs, individuality, and reduced the number of high frequency motifs (adult song features). This study suggests that the adult influence is proportional to young/adult ratio.