My major interests are in behavior, ecology, evolution and ornithology. Of these disciplines, I regard evolution as most important and consider behavioral problems mainly in the context of ecology and evolution. Hence my approach is largely that of behavioral ecology. Specific areas that concern me are animal sociality, reproductive biology, species interactions such as competition, the evolution of adaptations, and systematics. My present research is limited to birds and I am currently working on the coevolutionary interactions between parasitic birds and their hosts, egg recognition behavior in birds, social behavior and the determinants of dominance (especially status signaling in White-crowned Sparrows), the breeding biology of icterids, and the significance and origin of dialectal and individual variation in cowbird vocalizations. I also have some involvement in conservation programs dealing with endangered species that are threatened by cowbird parasitism. Recent publications that are indicative of my interests are cited in the list below.
I prefer that my graduate students choose thesis projects that are somewhat related to my own research interests since it is in such areas that I can provide the greatest help. Although I like to see my students develop their projects mostly on their own, I try to give them frequent and extensive feedback. This is done via weekly lab meetings during which all members of my group discuss their research or recently published papers and via frequent one-on-one discussion.