The social organization of captive groups of adult male and female starlings caught in different localities was studied to understand the possible social basis of song sharing. In the nonbreeding season, the social organization was based on within-sex groups or pairs and a few intersexual pairs. The pattern of song sharing clearly reflected the social organization. Members of the social pairs of females shared most of their songs, whereas males shared songs with other males to an extent that depended on their degree of social association. Song sharing was mostly restricted to birds of the same sex. The ability for adult vocal plasticity in both males and females may reflect the variety of possible social situations in this species.In the past decade, the importance of social input on the amount and plasticity of song learning and the choice of tutor has been increasingly demonstrated in different species (indigo buntings [Passerina cyanea], Payne, 1981; marsh wrens [Cistothorus palustris], Kroodsma & Pickert, 1984; white-crowned sparrows [Zonotrichia leucophrys],

Social influence on song acquisition was studied in 3 groups of young European starlings raised under different social conditions but with the same auditory experience of adult song. Attentional focusing on preferred partners appears the most likely explanation for differences found in song acquisition in relation to experience, sex, and song categories. Thus, pair-isolated birds learned from each other and not from broadcast live songs, females did not learn from the adult male tutors, and sharing occurred more between socially associated peers. On the contrary, single-isolated birds clearly copied the adult songs that may have been the only source of attention stimulation. Therefore, social preference appears as both a motor for song learning and a potential obstacle for acquisition from nonpreferred partners, including adults.

Vocal communication develops under social influences that can enhance attention, an important factor in memory formation and perceptual tuning. In songbirds, social conditions can delay sensitive periods of development, overcome learning inhibitions and enable exceptional learning or induce selective learning. However, we do not know how social conditions influence auditory processing in the brain. In the present study, we raised young naive starlings under different social conditions but with the same auditory experience of adult songs, and we compared the effects of these different conditions on the development of the auditory cortex analogue. Several features appeared to be influenced by the social experience, among which the proportion of auditory neuronal sites and the neuronal selectivity. Both physical and social isolation from adult models altered the development of the auditory area in parallel to alterations in vocal development. To our knowledge, this is the first evidence that social deprivation has as much influence on neuronal responsiveness as sensory deprivation.

Adult influence on song development was rarely investigated in complex social settings. We investigated the influence of the young/adult ratio on song learning in European starlings. Starling songs are composed of two categories: whistles and warbling. Warbling includes three parts: complex variable motifs, click motifs, and high frequency motifs. Song learning by young birds raised in group (G birds), in group with adults (GT birds) or in pair with one adult (IT birds) were compared. Song tutor choice, song sharing, and song quality varied with social context. The mere presence of adults in a group was not sufficient for young to develop all adult song features. Only IT birds chose adults as tutors. Social contact with only one adult enhanced acquisition of whistles, click motifs, individuality, and reduced the number of high frequency motifs (adult song features). This study suggests that the adult influence is proportional to young/adult ratio.

Turn-taking in conversation appears to be a common feature in various human cultures and this universality raises questions about its biological basis and evolutionary trajectory. Functional convergence is a widespread phenomenon in evolution, revealing sometimes striking functional similarities between very distant species even though the mechanisms involved may be different. Studies on mammals (including non-human primates) and bird species with different levels of social coordination reveal that temporal and structural regularities in vocal interactions may depend on the species' social structure. Here we test the hypothesis that turn-taking and associated rules of conversations may be an adaptive response to the requirements of social life, by testing the applicability of turn-taking rules to an animal model, the European starling. Birdsong has for many decades been considered as one of the best models of human language and starling songs have been well described in terms of vocal production and perception. Starlings do have vocal interactions where alternating patterns predominate. Observational and experimental data on vocal interactions reveal that (1) there are indeed clear temporal and structural regularities, (2) the temporal and structural patterning is influenced by the immediate social context, the general social situation, the individual history, and the internal state of the emitter. Comparison of phylogenetically close species of Sturnids reveals that the alternating pattern of vocal interactions varies greatly according to the species' social structure, suggesting that interactional regularities may have evolved together with social systems. These findings lead to solid bases of discussion on the evolution of communication rules in relation to social evolution. They will be discussed also in terms of processes, at the light of recent neurobiological findings.