MALE SONG AS A CUE FOR MATE CHOICE IN THE EUROPEAN STARLING

This study had two aims. First, we looked at individual differences in song characteristics between males of the European starling, and we related song behaviour to factors such as male age, pairing date, polygyny and male breeding success. Second, we experimentally tested whether song has an effect on female mating decisions. 1. During the breeding season, male starlings sing a very long and complex song consisting of a rapid succession of large number of different song types. We observed marked differences between males in average song bout length (a song bout was defined as a period of at least five seconds of song containing no pauses larger than 1.5 seconds) and in song repertoire size. Average song bout lengths ranged from 16 to 35 seconds. The individual repertoire size ranged from 23 to 67 song types. Repertoire size and average song bout length were positively correlated. 2. Both in the field and in captivity, yearling males sang shorter average song bout lengths and had smaller repertoire sizes than older males. 3. Males singing longer average song bouts and having larger repertoire sizes attracted females for pairing before their rivals with shorter average song bouts and smaller repertoire sizes. 4. Repertoire size and average song bout length were positively correlated with the number of females attracted and with male breeding success. The correlation between average song bout length and male breeding success remained when yearling males were excluded from the analysis. 5. Choice-experiments carried out in large outdour aviaries indicated that females mated significantly more often with males having larger repertoire size and singing longer average song bouts. 6. The overall results indicate that male song characteristics influence female mating decisions in the starling. It is concluded that the complex male song in the European starling has probably evolved as a result of intersexual selection by female choice. Finally, the possible role of song characteristics on female mate choice in the context of extra-pair copulations in songbirds is discussed.