REPERTOIRE TURNOVER AND THE TIMING OF SONG ACQUISITION IN EUROPEAN STARLINGS

In order to establish unambiguously whether a reputed open-ended learner, the European starling, could memorize new songs in adulthood, we exposed hand-reared male starlings to a series of either live conspecific tutors or tape recordings of conspecific song over a period of 18 months, and isolated them from any other exposure to conspecific song. The song motifs produced by the birds were compared with those of their tutors or training tapes to infer the time of motif memorization. We found that the starlings continued to memorize and produce new song motifs, both within and between breeding seasons, up to the age of at least 18 months. Not all the new motifs in the repertoires had been recently memorized; in some cases there was an apparent lag of a year and a half between memorization and production. There were no significant differences between live-tutored and tape-tutored groups in the timing of learning or in the rate of repertoire turnover (55-92% new motifs in each repertoire sample), although, as we have reported previously, live-tutored birds imitated a greater number of motifs and developed larger repertoires.