D Brandes

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

I, like William Blake and so many others for centuries, am fascinated and inspired by raptors (in my case, 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 particularly fascinating. How and why migrating raptors choose a particular route through mountainous terrain (e.g. the Appalachian Mountains) are interesting 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 7 years I have been 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 eagles react to terrain and weather conditions during migration (see list of publications below). 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. We are focused on these eagles as an indicator species for two reasons: (1) they are now known to be killed at many wind farms in the western US, and (2) available data suggests that their small, isolated eastern population may be at particular risk from ridgetop wind turbines along their migration paths and in their core wintering area in the central Appalachians. Risks may include both direct impacts (collisions) and indirect impacts such as displacement from traditional migration routes and wintering areas. Read our position paper on risks posed by wind turbines to raptors in the central Appalachians.

Our eastern Golden Eagle project has four components: 1) remote tracking of eagles using Argos GPS satellite-based systems and newly developed high-frequency GSM cellular-based units, 2) GIS-based statistical modeling of eagle 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 high resolution 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 Katzner’s Lab at WVU. We recently were pleased to learn that our project had won the 2011 Conservation Award from the Pennsylvania Society for Ornithology.

In a second project recently funded by a NASA Research Opportunities in Space and Earth Sciences Grant, I am part of a multidisciplinary group of researchers led by Gil Bohrer at Ohio State (see brief article here) that is developing new analysis and modeling tools for use with satellite telemetry data on animal movements from regional to continental scales. See the Movebank website here. My contribution will be providing researchers with methods for modeling orographic lift and other DEM-based landform analyses.

Finally, I am working 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

Publications on raptor migration, golden eagles, and wind energy

• Bohrer, G., D. Brandes, et al. 2012. Estimating updraft velocity components over large spatial scales: Contrasting migration strategies of golden eagles and turkey vultures. Ecology Letters, 15(2):96-103
• Katzner, T., B. Smith, T. Miller, D. Brandes, et al (many authors). 2012. Status, Biology, and Conservation Priorities for North America’s eastern Golden Eagle (Aquila chrysaetos) Population. The Auk, 129(1):168–176.
• Duerr, A., T. Miller, M. Lanzone, D. Brandes, et al (many authors). 2012. Testing an emerging paradigm in migration ecology shows surprising differences in efficiency between flight modes. PLoS ONE
• Katzner, T., D. Brandes, et al. 2012. Topography drives migratory flight altitude of golden eagles: implications for on-shore wind energy development. Manuscript in second revision Journal of Applied Ecology
• Lanzone, M., T. Miller, P. Turk, D. Brandes, et al. 2012. Flight responses by a migratory soaring raptor to changing meteorological conditions. Accepted, Biology Letters
• Ombalski, D. and D. Brandes, 2010. “Golden Eagle (Aquila chrysaetos)” in Terrestrial Vertebrates of Pennsylvania: A Complete Guide to Species of Conservation Concern, Johns Hopkins University Press, 528 pp.
• Brandes, D., Miller, T.A., and T.E. Katzner, 2009. “Wind Power Mortality” in Avian Ecology and Conservation: A Pennsylvania Focus with National Implications, Pennsylvania Academy of Science.
• Miller, T.A., Brandes, D., Lanzone, M.J., Ombalski, D., Maisonneuve, C., and T.E. Katzner, 2009. “Golden Eagle Migration and Winter Behavior in Pennsylvania” in Avian Ecology and Conservation: A Pennsylvania Focus with National Implications, Pennsylvania Academy of Science.
• Brandes, D., 2010. “Golden Eagle Migration through Central Pennsylvania” in Birds of Central Pennsylvania by N. Bolgiano & G. Grove, Stone Mountain Press.
• Brandes, D., 2008. Maryland Record Golden Eagle Flight, Dan’s Rock. Maryland Yellowthroat, Newsletter of the Maryland Ornithological Society, Vol 28, No 3
• Brandes, D. 2008. Unusual Golden Eagle photographed at Hawk Mountain. Hawk Migration Association of North America Hawk Migration Studies 24(2):12
• Brandes, D. 2006. Wind Power Development and Raptor Migration in the Central Appalachians. HMANA Hawk Migration Studies 31(2): 20-25.
• Ombalski, D., and D. Brandes. 2006. Pennsylvania Comprehensive Wildlife Conservation Strategy (CWCS) Species Assessment – Golden Eagle, Aquila chrysaetos.
• Brandes, D. and D.W. Ombalski, 2004. Modeling raptor migration pathways using a fluid flow analogy. J. Raptor Res. 38(3): 195-207.

Recent presentations on raptor migration, golden eagles, and wind energy

• Brandes, D., L Barrios, and A Rodriguez. 2011. Modeling the Interaction of Terrain and Wind to Quantify High-Risk Conditions for Eurasian Griffon Vultures (Gyps fulvus) at Wind Farms. Raptor Research Foundation Annual Meeting, Duluth, MN.
• Brandes, D., C Maisonneuve, J Tremblay, T Miller, T Katzner, and M Lanzone. 2011. Influence of High-Latitude Warming on Fall Migration Timing of Eastern Golden Eagles (Aquila chrysaetos). Raptor Research Foundation Annual Meeting, Duluth, MN. PDF of presentation
• Miller, T.A. M Lanzone, D Brandes, C Maisonneuve, J Cooper, K O’Malley, R Brooks, and T Katzner. 2011. Characteristics of Spring Migration of Golden Eagles (Aquila chrysaetos) through Eastern North America as Determined by GPS-GSM and Conventional Satellite Telemetry. Raptor Research Foundation Annual Meeting, Duluth, MN.
• Katzner, T., T. Miller, M. Lanzone, D. Brandes, R. Brooks, J. Cooper, C. Maisonneuve, J. Trembley, K. O’Malley. 2011. Golden eagles and Wind Energy in Eastern North America. U.S. Fish & Wildlife Service, Northeast Region Biologists Conference, Baltimore, MD.
• Katzner, T., T. Miller, M. Lanzone, D. Brandes, and R. Brooks. 2010. Threats to migrating golden eagles from development of wind energy: Golden eagles as an umbrella species for conservation. Ecological Society of America Annual Meeting, Pittsburgh, PA.
• Katzner, T., T. Miller, M. Lanzone, D. Brandes, and R. Brooks. 2010. Threats to migrating golden eagles from development of wind energy. Wilson Ornithological Society 2010 Annual Meeting, Geneva, NY.
• Brandes, D., G. Bohrer, J. Mandel, T. Katzner, T. Miller, M. Lanzone, C. Maisonneuve, and J. Tremblay, 2010. Raptor migration by computer – using modeling and satellite tracking data to fill in the gaps. 2010 Conference of the Hawk Migration Association of North America, Duluth, MN.
• Brandes, D., Katzner, T.E., Miller, T.A., Lanzone, M.J., and G. Bohrer, 2009. Simulation of Golden Eagle (Aquila chrysaetos) Migration Pathways through the Central Appalachians. Raptor Research Foundation Annual Meeting, Pitlochry, Scotland.
• Miller, T.A., Brandes, D., Lanzone, M.J., Ombalski, D., Maisonneuve, C., Brooks, R., and T.E. Katzner, 2009. Modeling Migratory Flight Characteristics of Eastern North American Golden Eagles (Aquila chrysaetos) Using High Frequency Telemetry Data. Raptor Research Foundation Annual Meeting, Pitlochry, Scotland.
• Miller, T., D. Brandes, M. Lanzone, D. Ombalski, C. Maisonneuve, R.P. Brooks and T. Katzner. 2009. Flight behavior of migrating golden eagles in the eastern USA: insights from high-frequency telemetry. Third Annual Conference of the Eagle Conservation Alliance, Ainsa, Spain.
• Brandes, D. 2009. Modeling flight paths for raptor conservation in a changing world. Pennsylvania DCNR Keystone Wild Notes, Summer 2009.
• Brandes, D. 2009. Appalachian wind energy and raptors: moving forward in a data vacuum. Presentation at the Appalachian Laboratory, University of Maryland. PDF version.
• Brandes, D. 2008. Appalachian wind energy development and migrating raptors: a collision course? Conservation through Education Lecture Series, East Stroudsburg University.
• Brandes, D., Katzner, T., Miller, T., Lanzone, M., Bildstein, K., and D. Ombalski. 2007. A Terrain-based Dynamic Model for Simulating Raptor Migration through the Applachians. Raptor Research Foundation & Hawk Migration Association of North America 2007 Joint Meeting.
• Miller, T., Brandes, D., Lanzone, M., Ombalski, D., Mulvihill, R., Brooks, R., and T. Katzner. 2007. Flight Characteristics of Golden Eagles (Aquila chrysaetos) Migrating Through Eastern North America as Determined by GPS Telemetry. Raptor Research Foundation & Hawk Migration Association of North America 2007 Joint Meeting.
• Lanzone, M., Miller, T., Brandes, D., Ombalski, D., Mulvihill, R., and T. Katzner. 2007. Golden Eagle(Aquila chrysaetos) Wintering Behavior in the Appalachian Mountains of Eastern North America using GPS Data from Satellite Telemetry. Raptor Research Foundation & Hawk Migration Association of North America 2007 Joint Meeting.
• Brandes, D. 2007. Raptor migration and the siting of utility-scale wind energy plants in Pennsylvania. Invited presentation at the Pennsylvania Wind-Wildlife Collaborative Technical Workshop.
• Brandes, D. 2005. Trickles of raptors: modeling migration with a fluid flow analogy. Invited presentation to the Raptor Society of Metropolitan Washington.