REPERTOIRE TURNOVER AND THE TIMING OF SONG ACQUISITION IN EUROPEAN STARLINGS

In order to establish unambiguously whether a reputed open-ended learn er, the European starling, could memorize new songs in adulthood, we e xposed hand-reared male starlings to a series of either live conspecif ic tutors or tape recordings of conspecific song over a period of 18 m onths, and isolated them from any other exposure to conspecific song. The song motifs produced by the birds were compared with those of thei r tutors or training tapes to infer the time of motif memorization. We found that the starlings continued to memorize and produce new song m otifs, both within and between breeding seasons, up to the age of at l east 18 months. Not all the new motifs in the repertoires had been rec ently 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 timin g 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.