My research centers on questions about the generation and maintenance of evolutionary diversity in natural systems. Using a combination of phylogenetic and comparative methodologies, I document temporal and geographic patterns of diversification and test hypotheses about the historical processes that produce those patterns. Birds serve as my primary model system and most of my work is conducted within an explicit historical framework provided by the phylogenetic analysis of DNA nucleotide sequences. This phylogenetic approach has an additional advantage in that the molecular data generated to test historical hypotheses often also bear on interesting issues from related fields such as systematics, molecular evolution, conservation, evolutionary ecology, and biogeography. I also supervise a large cadre of students and research professionals who work in the Fuller Evolutionary Biology Program at the Lab of Ornithology. My role in these additional projects varies from intense involvement to simple laboratory facilitation. I maintain a high authorship threshold, and much of this work done in my lab does not result in my co-authorship on the associated papers (about 20 papers to date in addition to those listed above on which I am an author). My overarching goal is to maintain a intellectually diverse and scientifically productive program that generates a steady output of high-quality research papers, and which simultaneously trains undergraduates, graduate students, and international interns to become future leaders in evolutionary ecology and conservation genetics.