INTRODUCTION

Vocal learning is a very widespread characteristic of songbirds, and a large variety of these learning processes has been described over the last decades. Learning can lead to different types of variation and results in song sharing that can be geographically localized and is then considered as “dialects.” The distribution of these variations can be limited to a few birds and/or cover large areas. Experimental studies have given precise information about the mechanisms involved, in particular in terms of “timing.” However, naturalistic validations may be necessary for us to fully understand the functional significance of vocal learning (see discussion of the sensitive periods, in the literature). There is a need for integrative studies and it is important to consider communication in its own context, which is that of social interaction (for language as a social act, see Goodwin 1990). A social organization needs an adapted communicative system, and comparative studies can give us hints about the evolutionary bases of vocal learning. Comparison can be made between species or phylogenetic groups but also between populations of a same species.

Likely candidates to help us to understand these processes are highly social animals that can adapt to different social environments. Starlings clearly correspond to this definition and here I examine through experimental and naturalistic studies the possible relation between song acquisition, song sharing and social organization.

The European starling (Sturnus vulgaris) occupies the largest geographic range of all the species of Sturnus (Feare 1984). It is present in Asia and in Europe from Scandinavia to Spain and Italy, and even in North Africa. It has also been introduced successfully in North America, New Zealand, and South Africa.