INDIVIDUAL RECOGNITION OF NESTLING DISTRESS SCREAMS BY EUROPEAN STARLINGS (STURNUS-VULGARIS)

Individual recognition of nestling distress screams by European starlings (Sturnus vulgaris) was assessed by comparing the responses of free-living parents to playbacks of screams recorded from their own young or from neighbouring chicks. Individual variation in the acoustic structure of distress screams was analysed to assess whether they were likely to afford an acoustic basis for individual recognition. Parents hearing screams of their own young were significantly more likely to make diving attacks on the speaker than parents hearing the screams of neighbouring chicks. Thus nestling screams appear to function as individually indentifiable calls for aid. Multivariate analysis of variance employing 9 acoustic parameters of nestling screams revealed significant differences among groups of screams recorded from different chicks, suggesting that screams could afford a suitable basis for individual recognition. Post-hoc F-tests suggest that the period and extent of rapid frequently modulations would provide the best cues to the identity of the caller.