The unifying theme of my research is to investigate biological diversity, primarily the evolutionary history of birds. I address two of the most challenging questions in avian systematics: 1- phylogenetics and biogeography of birds in the Old World tropics and 2- the deep relationships of the avian tree of life. By combining genetic, phenotypic, and geographic data, my lab addresses both fundamental questions – such as species-limits and phylogenetic relationships – as well as synthetic analyses using phylogenies to infer phenotypic evolution, biogeography, and diversification patterns. These issues are key to understanding the origins and maintenance of biodiversity and are crucial information for conservation biology.