David received his PhD from Florida State University. His work has focused on bird population ecology and conservation biology. He served for five years as Director of Research at the Sutton Avian Research Center, working primarily on prairie-chickens. He was also Head of the Department of Vertebrate Ecology at the Charles Darwin Research Station in the Galapagos Islands. His work was primarily with bird populations, but also included projects on invasive species, including predators, diseases, and parasites.