My main research focuses on how populations of birds vary in morphology, genetics, song, and/or ecology, especially in western North America. These data are used to study species limits, re-assess taxonomy, and examine contact zones between divergent lineages.

Projects (many collaborative) include studies on Steller’s Jays (Cyanocitta stelleri), Gray Jays (Perisoreus canadensis), Western Scrub-Jays (Aphelocoma californica), vireos (Vireonidae), Oak and Juniper titmice (Baeolophus inornatus / B. ridgwayi), Horned Larks (Eremophila alpestris), Spotted Towhees (Pipilo maculatus), and Sagebrush and Bell’s Sparrows (Artemisiospiza belli / A. nevadensis).

I have also been involved in the Grinnell Resurvey Project, which aims to resurvey historical sites in California to study changes in vertebrate communities, species distributions, and phenotypic/genotypic traits over the past century. Specimen-based resurveys have focused on the Mt. Lassen region, southern Sierra Nevada region, and western deserts.

Most of my field work has been concentrated in the western United States, including Alaska, Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming. I also have done field work in Canada (British Columbia, Newfoundland, Ontario, Quebec), Guatemala, Paraguay, and the Dominican Republic.

Field trip with students to Lassen County, California, 2011.

Featured image: Recording songs of Sagebrush Sparrows (Artemisiospiza nevadensis) in Mono Valley, California, 2012.