Communication acoustique et chants des oiseaux

This short trip into the sound world of birds aims at showing the reader the variety of the acoustic communication systems of the birds. Ten chapters are connected together according to the logical process of evolution and the increasing complexity of t he signal tunes. They show the role, during the evolution, of the antagonism between the advantages resulting from the simplicity and the stereotyped features of these signals and those resulting from their complexity and variety. The different species have found multiple solutions to this problem, holding simultaneously and rather paradoxically all the advantages : solutions in line with the constraints of the environment, whether acoustical or ethological. In this evolution, the need to maintain the propagation of the song in the most various environments (chapter II), its specificity (chapter III) and the marking of populations having common characteristics (chapter VIII) has favoured the simplification and the stereotyped feature of the song. On the other hand, the constraints of the sexual selection (chapter IV) and the advantages resulting from the synchronisation of the neighbours' activities (chapter V), of the acquisition of a vast repertoire of songs (chapter VII) and of the emission (o f sound) by the singer of informations about its personality (chapter IX) have led th s evolution towards more complexity and diversity. The leap into complexity was only made possible by a genial invention : culture. Indeed, learning a song makes it possible to pass on , from generation to generation, its characteristics by oral tradition. Freed, as it i s, from its genetic support, evolution has quickly produced very complex communication systems, that, among other things, account for the great success of some species.