Andrew Dennhardt
B.S. Zoology, Southern Illinois University  
M.S. Wildlife and Fisheries Resources,West Virginia University  
e-mail: dennhard*at*msu.edu  

I am currently a doctoral student at Michigan State University, and my primary research interests are in factors associated with species distributions, animal movements, and how these things impact population dynamics. While at West Virginia University, I received my Master of Science degree in Wildlife and Fisheries Resources under the direction of Dr. Todd Katzner. The primary focus of my research project was to model the migration paths of golden eagles (Aquila chrysaetos) during autumn in eastern North America. Another objective of this project was to estimate a population size for golden eagles in this region. We did this by integrating information from our movement models and historic data of migration counts in a unique mark-recapture analysis. With our movement models we were able to identify new areas where golden eagles migrate in the Appalachians, which may influence future energy development plans in the eastern United States and other areas. Our estimates of population size are useful for conservation and management goals for this species.

The golden eagle is a large raptor species of the genus Aquila and enjoys an impressive range throughout the Northern Hemisphere. Golden eagles in North America are primarily migratory in the east while, in the west, there are year-round populations in the contiguous states and another migratory population that summers in Alaska. Eagles in the east migrate from breeding areas in northeastern Canada during fall to overwinter in the Appalachian Mountains and parts of the Midwest. In the spring, the eagles then migrate back northward to resume annual breeding.

Land-use by golden eagles during the fall and spring is pertinent to future management decisions concerning wind energy development on mountain ridges. Mountain ridge tops produce strong wind conditions that promote passive soaring in large raptors—an energy conservation strategy that subsidizes flight. As is expected, such wind conditions also provide an available energy resource for corporate and private enterprise. Eagle collisions with wind turbines have been documented in areas of the western United States, such as at Altamont Pass in Alameda County, California. Such collisions have produced a detrimental mortality factor for a species with low fecundity, like the golden eagle. Verifying when and where eagles are moving during migration in the east may help wildlife managers mitigate these negative influences on migratory bird populations, perhaps in the broader raptor group as well. In addition to land-use findings, population size estimates will help shape conservation goals and other management objectives.

In this project, our team produced valuable insights into golden eagle population ecology that will contribute to ongoing conservation and management efforts for these majestic birds amidst the growing demand for renewable energy resources.