Vocal systems of communication in songbirds have evolved under several lines of factors such as phylogeny, socials constraints and variation of habitats. We hypothesized here that social life could have shaped vocal structures in response to different “social needs”. We focused on three phylogenetically close related species of South African sturnids that presented different social systems: Onychognathus nabouroup is a colonial species whereas Lamprotornis nitens and Spreo bicolor form communal breeding of different size. Recordings were all done in the Eastern Cape areas in order to limit potential geographical variations. Our results showed that differences in song structures of these species presented a gradient following the social system. Colonial species (O. nabouroup) songs tended to have discontinuous sequences of motifs, small family group species (S. bicolor) presented both short and loud sequences of song and long and variable sequences of song whereas large family group species (L. nitens) presented long and variable sequences of song. These results suggested that social life could have exerted strong selection pressures on vocal communication, modelling vocal signals in terms of structure and organisation, in relation to social life.