research projects
openwings
Birds are the single most diverse lineage of amniotes (10,000+ species) and occur in almost every terrestrial environment. Despite being among of the most thoroughly studied vertebrate clades, the spatial and temporal framework for the origin of different avian lineages remains poorly understood. The OpenWings Project aims to use targeted sequence capture and massively parallel sequencing to produce a taxonomically complete phylogeny of all bird species that will be calibrated using a comprehensive sample of rigorously-analyzed fossils. The OpenWings Project is supported by the National Science Foundation.
evolutionary history of parrots
Parrots (Order: Psittaciformes) are a diverse and pan-tropical clade known for their colorful plumage, intelligence, and are among the most threatened group of birds. Studying the evolutionary history of these interesting characteristics is contingent on knowing how parrots are related across their phylogenetic tree. Recent efforts, largely fueled by small fragments of DNA sequence, have provided resolution to higher-level relationships across the clade. However, the compound effects of limited taxon sampling and few genetic markers have yielded a tree with many poorly resolved and unclear relationships. Currently, we are using genome-wide markers and nearly complete species-level sampling to produce a phylogenomic tree for parrots. We are using this robust tree to test models of color evolution, species and phenotypic diversification across space, and revise the taxonomy of parrots.
Fig. from Merwin et al. (2020) showing color data of lories and lorikeets.
Fig. from Provost et al. (2018) showing behavioral responses of Northern Cardinals to song types.
Integrative models of avian speciation
Classical models of speciation consider taxa to be passive participants in a dynamic landscape where population isolation and the maintenance of gene flow is dictated by the formation of physical barriers. However, decades of research show that biotic communities harbor high variation in evolutionary histories among co-distributed taxa, and these genetic patterns are not readily explainable by the waxing and waning of barriers. We are focused on explaining how these diverse evolutionary histories arise by developing “bottom-up” diversification models where we integrate genomic and phenotypic data, field-based experiments, and spatially explicit demographic modeling. Our aim is to model how neutral and adaptive genetic variation is produced across the landscape, how it varies across communities, and how species traits influence diversification, persistence, and extinction. We are working on various projects that include birds occuring in the Nearctic, the North American warm deserts, Amazonia, and Middle America.