Golden Eagles Fly Far and Wide in the Mojave

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Golden eagles in the Mojave Desert travel farther, to different areas, and at different times of the year than previously understood, according to research by the U.S. Geological Survey and partners from other federal agencies, academia and the private sector. 

Image: Female Golden Eagle with GPS-GSM Transmitter
From 2012-2013, telemetry data were collected from nine eagles outfitted with a backpack holding a global positioning system-global system for mobile communications, or GPS-GSM, telemetry system. The telemetry system recorded and stored a GPS location every 15-minutes and sent the locations, via the GSM – or mobile phone – network, to a server once per day.
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BOISE, Idaho. — Golden eagles in the Mojave Desert travel farther, to different areas, and at different times of the year than previously understood, according to research by the U.S. Geological Survey and partners from other federal agencies, academia and the private sector. 

Conservation plans, such as the Desert Renewable Energy Conservation Plan, or DRECP, are being developed for the Mojave Desert, which stretches over the borders of California, Nevada and Arizona. The goal of the plan is to protect species like the golden eagle while allowing for renewable energy development, a sector that is seeing substantial growth.

“Renewable energy projects have affected large numbers of eagles elsewhere, either directly through fatal encounters with energy infrastructure, or indirectly through loss of habitat,” said Melissa Braham, West Virginia University biologist and lead author of a new article published in the journal Biological Conservation. “This new study provides land managers with a better understanding of how the small population of golden eagles breeding in the Mojave Desert may be exposed to risk from renewable energy development in the area.”

Telemetry data were used to determine the overall size of each eagle’s home range, what habitat types were included in the eagle’s home range, and the timing of eagle movements within that home range. The telemetry data documents golden eagle movement with a higher level of accuracy than ever before.

The timing in golden eagle movements is likely linked to their breeding ecology and the seasonal variation in weather and prey availability. Researchers found that eagles did not expand their home ranges equally in all directions. Instead as home ranges enlarged, the eagles favored movement uphill, from the desert to the mountains.

“Conservation measures outlined in the DRECP focus on protecting golden eagle nests by creating a narrow buffer around the nest,” said USGS wildlife biologist Todd Katzner. “This study shows eagle habitat use is complex and often extends to areas beyond the DRECP conservation buffer. Managers planning for DRECP’s adaptive approaches to habitat conservation may wish to consider the desert golden eagles’ seasonal changes in behavior and reliance on habitat outside the DRECP boundary.”

“This study along with another recent article provide important baseline information on movement and distributions of protected raptor species within the DRECP,” said Katzner. “They also provide a framework to evaluate the risk that wildlife populations face from development in general, and of renewable energy, across these biologically important desert habitats.”

The study was funded by the Bureau of Land Management and led by a team of scientists from West Virginia University, Cellular Tracking Technologies, the BLM, the American Eagle Research Institute, the U.S. Forest Service, and the USGS.