Behavioral mechanisms of reproductive isolation in avian hybrid zones

Sexual signals and mating behaviors influence whether sympatric species interbreed, and can therefore promote or impede behavioral reproductive isolation between species in secondary contact. Traditionally, research on sexual selection and hybridization has focused on the importance of interspecific mate choice and species discrimination from the perspective of choosy females, and competition from the lens of aggressive and indiscriminate males. I examined two different avian systems to compare the role of male and female competition on hybridization: white-crowned sparrows on the west coast of the US, and sex-role reversed jacanas in Panama. Using genomics and experimental field techniques, I tested morphological, behavioral, and historical factors that influence patterns of gene flow between lineages. I found that contrary to traditional expectations, divergence in male competitive signals can promote reproductive isolation, and female competition can facilitate hybridization.