Recent research projects
Mercury
Golf Courses
Created Wetlands
Hippocampus and Migration
Optimal Foraging
Philosophy: Since tenure I have published papers on cognitive ecology of migration, wetland mitigation, food caching, social dynamics of wintering flocks, source-sink population dynamics, conservation on golf courses, feather-degrading bacteria, and mercury contamination. That’s a lot of sub-disciplines, none of which I have fully mastered. But this breadth has provided opportunities for student researchers with many interests and skill levels. What I strive for in research is not the quest for a particular bit of knowledge, but the creation of a climate of discovery in which everyone involved knows that we are doing the real thing. Below I summarize the three main areas in which my research has made contributions.
Effects of land use on bird populations:
Mercury Pollution: My current focus is on mercury contamination in the headwaters of the Shenandoah River in central Virginia. This project arose after a conversation with a toxicologist from the US Fish & Wildlife Service who wondered aloud whether mercury that leaked into the South River from 1929-1950 was harming birds. While everyone knows that mercury is bad for animals, the consensus ends there. After three field seasons my lab has made major discoveries about the movement of mercury through the food chain and the effects (and lack thereof) of various levels of mercury on reproduction and survival in numerous bird species. Most significantly, we have discovered that mercury from a river can enter the surrounding terrestrial food chain and accumulate in terrestrial spiders that are eaten by songbirds. This leads to higher levels of mercury in forest songbirds than in fish-eating birds, which have long been considered the only group at risk. Kelly Hallinger, Rachel Fovargue, and Mikaela Howie are currently working on the mercury question, in collaboration with the South River Science Team, and several papers are coming out. I am co-director of a faculty group at William & Mary studies mercury as an international hazard from an interdisciplinary perspective. (More)
Created Wetlands: A different project that was inspired by student curiosity is the potential conservation role of wetlands that are created by developers to replace those destroyed during construction. Once again, a brief conversation with a seminar speaker led to three papers and an Honors and a Masters thesis that pushed forward a neglected area of the wetland conservation issue.
Behavioral Ecology:
Brain and bird migration: The Rosetta stone of modern neurobiology would be a study system in which a change in behavior could be linked to a change in cognition, and this in turn could be linked to a change in a brain structure. I identified such a study system after arriving in Virginia. A sparrow called the junco migrates each fall from Canadian breeding grounds to its temperate winter home in Virginia. But before the retreat of the last glaciers 10,000 years ago, juncos didn’t have to migrate from the then cold climate of Virginia. To this day, there is a population of non-migratory juncos surviving year-round in relict northern hardwood forests atop the tallest Appalachian peaks. I capitalized on this natural evolutionary experiment to study the effects of evolving migration behavior on cognition and brain structure. Through five years of winter fieldwork in the mountains I found that migratory juncos have better spatial memory than non-migrants, and this is backed up by more nerve cells in a brain structure called the hippocampus (paper). This study system has great potential as a model for tracking how evolution can alter behavior, mental ability and brain anatomy in tandem. I am currently preparing the final manuscript from this study, in which I deprived juncos of the experience of migration and found that the migratory junco’s hippocampus is larger than that of non-migrants before migration (the result of evolutionary change) and also enlarges further during the migration (the result of experience).
Optimal Foraging: Just before arrival at William & Mary, I began a series of studies on birds that consume hard-shelled food such as walnuts or clams. Some species carry these impenetrable prey items high into the sky so that they will shatter on the ground below. This is a complex skill, and carrying the food items too high, or not high enough, will result in wasted energy. I have shown (papers) that crows perform this task with close to the theoretical maximum efficiency when they are adults, extending the classic work by Zach on crows and snails that kicked off the optimal foraging research revolution in the 1970’s. With undergraduates at William & Mary, I have pursued this question on a local population of clam-dropping gulls to determine how young birds acquire this sophisticated behavior – through imitation, trial-and-error, or simply following a genetically-inherited set of behavioral rules. A paper describing that first seven years of work on gulls is in revision.
Summary: My research is diverse because this provides more opportunity for truly independent student research and best suits the environment of close faculty mentorship that is the hallmark of science education at The College of William & Mary. While education is always on my mind, research is my passion, and I pursue it with the same professionalism and zeal that I would if research were all I did.
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