Dan is an unconventional ecotoxicologist trained in both behavioral ecology and avian biology. His lab documented that mercury pollution from the Shenandoah River watershed is crossing ecosystem boundaries, entering the terrestrial food web, and biomagnifying through invertebrates, especially spiders, into songbirds. For six years Dan and his students documented the fitness consequences of food web mercury in the floodplain of the Shenandoah watershed, publishing ~25 papers on the contaminant's effects on reproductive output, endocrinology, singing behavior, immune responsiveness, survivorship and other aspects of fitness. Now, they are using the same approach to uncover the effects of other pollutants, such as dioxins and PCBs, in some of America’s other rivers, from the Mississippi to the Passaic.

The lab also studies pollutants and birds indoors, using William & Mary's zebra finch colony to examine the mechanisms behind mercury's toll, using experimental approaches to document causation rather than merely the correlations discovered in the field. This approach has been fruitful, demonstrating that mercury was indeed responsible for the detrimental effects found at the Shenandoah River. Dan and his students have published ~25 more papers from this experimental work.

Our lab has published over 100 peer-reviewed articles in a wide variety of fields, including microbiology, behavior, neuroscience, ecology, wildlife management, conservation, and toxicology. Of these, most have been in the upper echelon of journals in each field, and some have been in the most prestigious journals, such as these articles in Science, Nature, Environmental Science & Technology and Landscape & Urban Planning. Dan’s articles have been cited an average of 84 times each, according to Google Scholar, generating an h-index of 40 (i.e., 40 articles cited at least 40 times).

Since becoming an assistant professor in 1996, he has closely mentored ~200 undergraduate students for one or more years, as well as ~40 master's students. Dan is a Chancellor Professor of Biology and has been the director of the William & Mary's premier merit scholarship program, the 1693 Scholars, for 18 years. Before his career at W&M, he was a research fellow or student at University of California-Davis, Oxford University, Indiana University (PhD 1993), and Cornell University (BS 1985).

Dan teaches Animal Behavior, Human-Wildlife Conflicts in the Anthropocene (a.k.a. “Florida field class”), Ornithology, and several pre-med experiential learning courses (including “Birding and Medicine”). He also has written a monthly column on birds in the Virginia Gazette, one of America’s oldest surviving newspapers, for over 20 years and is occasionally seen or heard in the national media commenting on bird-related conservation issues. He has been featured on Nightline, Frontline, NPR, BBC, and in the New York Times and Audubon magazine. Dan has two daughters, both named after birds, who attended University of Virginia and William & Mary.