International Journal of Comparative Psychology

Considerable geographic variation often exists in behaviors of different populations of a species. Of key interest are the mechanisms generating this variation, and the impact this variation may have on gene flow between two populations. Here, we review two sets of studies of brown-headed cowbirds, Molothrus ater, indicating that the social background of an individual can impact its ability to court, pair, and mate with individuals of one behavioral tradition/population relative to individuals of another behavioral tradition/population. The first studies involved two populations with extant differences in mating behaviors and found that young cowbirds of one population that interacted over ontogeny with members of a behaviorally-distinct population developed courtship behaviors and mating patterns similar to members of that ‘foster’ population. The second set of studies tested the possibility of generating distinct systems of mating behavior within one population and found that young cowbirds that interacted over ontogeny with different age-structured social groups developed effectively distinct mating patterns. Thus, social traditional processes in cowbirds can create, maintain, or dissolve population-level differences in courtship and communication. This work highlights the power of the social environment to act as a structuring ecology for behaviors fundamental to reproductive success.