Ecological and evolutionary drivers of geographic variation in songs of a Neotropical suboscine bird: The Drab-breasted Bamboo Tyrant (Hemitriccus diops, Rhynchocyclidae)

Understanding the evolutionary and ecological mechanisms that shape the spatial divergence of signals involved in reproductive isolation is a central goal in studies of speciation. For birds with innate songs, such as the suboscine passerine birds, the integration and comparison of both genetic and ecological factors in explaining song variation at the microevolutionary scale is rare. Here we evaluated the evolutionary and ecological processes underlying the variation in the songs of the Atlantic Forest endemic Drab-breasted Bamboo Tyrant (Hemitriccus diops), testing the effects of both stochastic and adaptive processes, namely the Stochastic and Adaptation Acoustic Hypotheses, respectively. We combined vocal, genetic and ecological (climate and forest cover) data across the species’ range. To this end, we analyzed 89 samples of long and short songs. We performed analyses on raw and synthetic data song variables with linear mixed models and multivariate statistics. Our results show that...