Gustavo's general research goal is to understand the evolutionary mechanisms underlying the diversification, phenotypic evolution, historical biogeography, and distributional patterns of birds. Specifically, he is interested in understanding how the interaction between phenotypes and the environment affects diversification patterns across time and space. To that end, Gustavo integrates genetic, phenotypic, ecological, behavioral, and distributional data obtained directly in the field, in the lab, and in scientific collections.