Song organization and song control in social birds
Résumé
In 1970, Marler set the idea of a parallel between human speech and birdsong, emphasizing the many common properties in vocal development of both infants and songbirds. Among the parallels found between human language and birdsong development, the importance of learning from conspecifics has taken an increasing part in recent findings, and the nature and intensity of social influences on vocal development have become a crucial question. In this paper, I will use the European starling, a highly social songbird, as an example of how social factors can strongly influence vocal communication and perception. In particular, after explaining how starlings perceive and process song, I will report results of an experiment aiming at investigating the importance of social bonds versus auditory information on song acquisition and processing. In this study, hand-raised starlings were kept in different social conditions (raised with peers and adults, raised in pairs, and raised alone) but received the same auditory information (containing live interactions between adults). Results of this experiment showed that social experience could override auditory information, and that both physical and social isolation from adult models altered the development of the main central auditory area. These results raised general questions about the role of social constraints on both the development and the evolution of vocal communication.