Threats From Wind Energy Turbines Identified for Migrating Golden Eagles
Wind power is a fast-growing industry with important implications for energy policy and broad potential to affect some migratory wildlife. Golden eagles are a species known to be at risk from wind energy development and in some areas are killed in large numbers by turbines. At other sites, however, turbines kill no eagles; thus, something about the site of turbines affects the risk to eagles. A national team (including two Forest Service scientists) is examining causes of these site differences, with the hope of mitigating this problem.
Golden eagles migrate in large numbers through the central Appalachian Mountain region. This research uses novel animal tracking systems to identify specific minute-by-minute flight decisions eagles make on their migration and the potential for those decisions to increase the risk to birds from wind energy development in this economically important region. The team uses high-frequency Global Positioning System-Global System for Mobile Communications telemetry systems to collect data at 30-second intervals, to understand the intimate details of how birds fly.
Data collection in Eastern North America shows that (a) flight altitude of eagles is determined in part by the topography over which they are flying; (b) that use of low-altitude orographic (deflected) lift is less efficient than use of a thermal-gliding strategy that also pushes birds relatively higher into the sky and reduces the risk to eagles; and (c) that with increasing wind speeds, eagles are flying at lower altitude than at lower winds.
This work is being expanded to the California desert, where the team is working with the Bureau of Land Management to characterize and minimize risk to eagles from development of wind energy on public lands there. This project is in collaboration with biologists from the Rocky Mountain Research Station in Arizona and collaborators from State and Federal agencies nationwide.
Forest Service Partners