Yellow Cardinal (Gubernatrix cristata) males respond more strongly to local than to foreign dialects

Abstract

Bird song is a culturally transmitted behavioural trait strongly tied to territory defence and mate attraction in oscine passerines. Divergent song variations can appear in different populations of the same species as a consequence of multiple factors generating geographically distinct songs also termed dialects. Most studies show that males react more strongly towards local dialects, potentially as a by-product of evolutionary divergence between populations, although other hypotheses have been suggested. In addition, females are hypothesized to show stronger responses to local songs as this may lead to greater reproductive success. In this context, song may become a prezygotic barrier for reproduction. The Yellow Cardinal Gubernatrix cristata is an endangered species of the South American thorny shrubland that has suffered from population fragmentation due to habitat destruction and its capture for the illegal wildlife trade. Genetically different groups that sing their own dialect have been studied in the context of a conservation programme that intends to restore and preserve natural populations by releasing individuals that are recovered from the illegal pet market back into their area of origin. Although dialects have been identified, it remains unknown whether there is vocal recognition between the populations. In this study, we performed playback experiments in two populations and found that male Yellow Cardinals reacted more strongly to the local dialect, although the foreign dialect was still recognized. This information is important as it is not always possible to genetically assign an individual to its geographical origin before release, which could contribute to a secondary contact scenario where dialects play a critical role for settlement and reproduction.