Raptor Flight Modeling & Wind Energy

“When thou seest an Eagle, thou seest a portion of genius; lift up thy head!” – William Blake

Like William Blake and so many others for centuries, I am fascinated and inspired by eagles (Golden Eagles in particular). As a hydrologist I have a keen interest in the effects of topography in natural systems, and thus I find the interaction of topography and raptor flight to be a particularly compelling area of research. How and why migrating eagles choose a particular route through mountainous terrain (e.g. the Appalachian Mountain chain) are questions that I have been able to shed some light upon through the application of models based loosely on principles of fluid flow.

For the past 10 years I have spent much of my research time collaborating with scientists from West Virginia University, Quebec Ministry of Natural Resources, Cellular Tracking Technologies, and Hawk Mountain Sanctuary to better understand and quantitatively model how golden eagle flight is influenced by terrain and weather conditions during migration. This work is particularly relevant because wind energy development is rapidly expanding throughout the Appalachian region, particularly in the higher elevations used extensively by golden eagles. They are known to be vulnerable to turbine strikes at many wind farms in the western US. Risks may include both direct impacts (collisions) and indirect impacts such as displacement from traditional migration routes. Read the recent news feature on wind turbine risks to birds and bats published in the journal Nature.

Our Golden Eagle project has four components: 1) remote tracking of eagles using newly developed high-frequency GSM cellular-based units, 2) GIS-based statistical modeling of eagle ecology and flight behavior over its annual cycle (breeding-migration-wintering), 3) camera-trapping at sites throughout the Appalachians to assess wintering populations, and 4) mathematical modeling of migration pathways using digital topography and weather data (my specialty). The research has been supported by grants from PA DCNR Wild Resource Conservation Program, several PGC State Wildlife Grants, and a DOE grant through the program “20% Wind by 2030: Overcoming the Challenges”, and has many cooperators at various state agencies and nonprofit organizations. Further information about the project can be found at the EGEWG website. The project won the 2011 Conservation Award from the Pennsylvania Society for Ornithology, and a 2013 Research and Management Partnership Award from the US Forest Service.

IMG_4255smallIn a second project funded by a NASA Research Opportunities in Space and Earth Sciences Grant, I was part of a multidisciplinary group of researchers led by Gil Bohrer at Ohio State to develop new analysis and modeling tools for use with telemetry data on animal movements from regional to continental scales. See the Movebank website here and the Science Daily article about the project. My contribution is providing researchers with methods for modeling orographic lift and other topographic analyses. This project has led to some research with Hawk Mountain Sanctuary on the migration of Turkey Vultures. Although a bit homely to look at, they are among the most efficient soaring birds in the world, capable of using very weak thermals and updrafts to fuel their movements across the landscape.

Finally, I have worked with colleagues in Spain to better understand and predict high-risk conditions for griffon vultures at wind-energy sites near the Strait of Gibraltar (see modeling work in Spain). This is a region where researchers have been studying wind energy and soaring bird interactions since the 1990s.

Link to Eagles in the California Desert project.

Link to FlightPath model developed while I was on sabbatical at Hawk Mountain’s Acopian Center for Conservation Learning.

Link to Tussey Mountain Spring Eaglewatch, which I started while doing my Ph.D. at Penn State

My raptor CV