Extended song learning in wild European starlings

The songs of wild adult European starlings,Sturnus vulgaris, were recorded over successive years to determine whether repertoire size and composition changed between years. Repertoire-size estimates increased between the first and last year of recording for five of seven males that were at least 2 years old when first recorded. All seven birds showed extensive changes in the composition of their repertoires. Many phrase types were dropped from the repertoire, and others were modified. All birds added many new phrase types to their repertoires between years. These results indicate that extended song learning occurs in adult starlings, even in birds that are at least 4 years old, and that repertoire size is correlated with age in this species. The influence of song repertoire size on male-male competition and possibly female mate choice may be related to its value as an indicator of male age.