Age-related changes of song traits in female European Starlings (Sturnus vulgaris)

Abstract

AbstractIn contrast to male bird song, female song complexity, learning and expression have received much less attention. Female European starlings can produce song of a comparable complexity as males and are also capable of adult vocal learning. Here we recorded song during 3 successive years and investigated variation in song traits (song complexity, song duration and song versatility) in relation to age in captive adult female starlings. We looked at whether individual song traits differ among different age classes (cross-sectional analyses) and whether they change over successive years (longitudinal analyses). Further we studied the repertoire turnover throughout the years, female song sharing in the first year of recording and whether different song traits consistently vary among females across the years. Overall, both cross-sectional and longitudinal analyses showed that repertoire size significantly declined with female age, suggesting that some constraints exist in adult females to maintain large repertoires. Song duration and song versatility appeared to be unrelated to age. Female starlings intensely modified their repertoire across the years by adding new/deleting old phrase types, suggesting a high plasticity as reported in males. Females showed a high variation (between 14% and 83%) in sharing their repertoire, with older females having higher song sharing rates. The individual differences in song complexity and performance were repeatable across the years, which may suggest that song in female starlings is a potential quality indicator trait.