Avian Systematics and Taxonomy

More than 10,000 extant species of birds are the result of billions of years of evolution on our planet. We reconstruct the evolutionary history of birds and infer the biological processes that underlie avian biodiversity. We use population and comparative genomics to generate phylogenies that depict how species are related to each other and examine demographic history. We generate new knowledge that improves our taxonomic classification of birds, both within and among species. Systematic and taxonomic work within the Mason Lab has focused on tanagers, finches, and larks, among other lineages of birds.

Evolution and Ecology of Bird Song

Avian vocalizations are remarkably diverse and are involved in many aspects of bird biology, such as territoriality and mate choice. Media archives of high-quality bird recordings have opened new avenues of research on the evolution and ecology of vocal displays at different taxonomic scales. We examine associations between vocalizations and variation in other aspects of bird biology, such as plumage elaboration and habitat acoustics. Research on bird song within the Mason Lab has focused on studying variation among populations within species, such as the Fox Sparrow (Passerella iliaca), and variation among species within clades, such as tanagers (Thraupidae). Looking ahead, we are interested in examining the evolution and development of the syrinx as a complex organ that produces avian vocalizations.

Evolution and Ecology of Color

Birds span the rainbow of colors (and then some!). We use an expanding toolbox of color science methods, including spectrophotometry and digital photography, to quantify variation in reflectance, pigmentation, and patterning among populations and species. We study the evolution and ecology of bright colors involved in sexual selection, such as those boasted by many tanagers (Thraupidae), as well as the evolution and ecology of cryptic coloration shaped by natural selection, as seen in larks (Alaudidae). We are also interested in how coloration impacts other aspects of avian biology, such as thermoregulation.


Biodiversity is unevenly distributed across the Earth’s surface, and each species’ evolutionary history is shaped by geographic features that have themselves changed over time. We are interested in how variation in dispersal, migration, and species’ ranges have evolved. Within a phylogenetic comparative framework, we reconstruct the biogeographic history of avian lineages to infer the timing and sequence of events that have led to birds’ current distributions. We are also interested in how these distributions change over contemporary time scales.

Louisiana Avifauna

Louisiana is home to a diverse assemblage of birds and important ecoregions, including the Mississippi River Delta and the Mississippi Flyway. Both breeding and wintering birds rely heavily on various habitats in Louisiana with regional and global importance. For example, more than half of the Sandwich Terns (Thalasseus sandvicensis) found in the United States breed in Louisiana. Other species, such as Tricolored Heron (Egretta tricolor) and Black Skimmer (Rynchops niger) also rely heavily on Louisiana’s rich coastal ecosystems. We are interested in studying the distribution and phenology of Louisiana’s birds by combining bioacoustic surveys and general and targeted collecting of specimens to establish new baselines for future generations.

Human Impacts on Birds

Our planet is rapidly changing with dramatic impacts for wildlife and biodiveristy. Natural history collections provide the ultimate long-term dataset to study how birds are responding to anthropogenic impacts. We use spatial and temporal series of museum specimens to examine how birds are impacted by anthropogenic activity, such as agriculture, pollution, and global warming. Work in the Mason Lab has focused on different regions and anthropogenic activities, such as the rise of agriculture in the Imperial Valley of southeastern California.