Geographic Patterns and Evolutionary Processes of Avian Diversification

Understanding the patterns and processes that generate biodiversity is a unifying theme in evolutionary biology. This dissertation investigates how geography and evolutionary history interact to shape patterns of avian diversification across multiple spatial and taxonomic scales. My first chapter uses a near-complete timetree of white-eyes (Zosteropidae) to show that island lineages exhibit elevated speciation rates relative to continental lineages, highlighting Indo-Pacific archipelagos as engines of diversification. The second chapter reconstructs a comprehensive phylogenomic tree and historical biogeography of the honeyeater genus Myzomela, uncovering non-monophyly in several species complexes and revealing repeated colonization of Wallacea and the South Pacific followed by rapid radiations. In my third chapter, I integrate genomic, plumage, and vocal data to reveal patterns of divergence, gene flow, and discordant geographic clines in the Curve-billed Thrasher (Toxostoma curvirostre) complex from the North American Southwest. Overall, these chapters illustrate the dynamic interaction between geography and evolutionary processes in the generation and maintenance of avian diversity.