Eagle fatalities are reduced by automated curtailment of wind turbines, Christopher J.W. McClure, Brian W. Rolek, Leah Dunn, Jennifer D. McCabe, Luke Martinson, Todd Katzner.Journal of Applied Ecology 2021 Jan


Collision‐caused fatalities of animals at wind power facilities create a ‘green versus green’ conflict between wildlife conservation and renewable energy. These fatalities can be mitigated via informed curtailment whereby turbines are slowed or stopped when wildlife are considered at increased risk of collision. Automated monitoring systems could improve efficacy of informed curtailment, yet such technology is undertested. We test the efficacy of an automated curtailment system—a camera system that detects flying objects, classifies them, and decides whether to curtail individual turbines to avoid potential collision—in reducing counts of fatalities of eagles, at Top of the World Windpower Facility (hereafter, the treatment site) in Wyoming, USA. We perform a before‐after‐control‐impact study, comparing the number of eagle fatalities observed at the treatment site with those at a nearby (15 km) control site without automated curtailment, both before and after the implementation of automated curtailment at the treatment site. After correcting for carcass detection probability and scaling fatality estimates to turbine‐years, we estimate that the number of fatalities at the treatment site declined by 63% (95% CI = 59% – 66%) between before and after periods while increasing at the control site by 113% (51% – 218%). In total, there was an 82% (75% – 89%) reduction in the fatality rate at the treatment site relative to the control site. Synthesis and applications. Automated curtailment of wind turbine operation substantially reduced eagle fatalities. This technology therefore has the potential to lessen the conflict between wind energy and raptor conservation. Although automated curtailment reduced fatalities, they were not fully eliminated. Therefore, automated curtailment, as implemented here, is not a panacea and its efficacy could be improved if considered in conjunction with other mitigation actions.

Wind energy is an important technology as society moves toward identifying green sources of energy. However, wind turbines can cause a negative impact on local wildlife, including bird and bat fatalities, which occur when they collide with rotating turbine blades. In a recently released study, “Eagle fatalities are reduced by automated curtailment of wind turbines,” in the Journal of Applied Ecology, researchers from The Peregrine Fund, Western EcoSystems Technology, Inc., and the U.S. Geological Survey, tested an automated computer vision system called IdentiFlight. This system is designed to use cameras and machine learning to detect eagles near turbines, so turbines can be shut off, reducing fatalities of eagles at wind energy sites. Use of the new IdentiFlight system resulted in an 82% reduction of eagle fatalities.

IdentiFlight is an automated curtailment system consisting of cameras and software programmed for detecting flying objects, classifying them, and stopping turbines from spinning when an eagle is at threat of collision. The study to test IdentiFlight was performed at Duke Energy Renewables’ Top of the World Windpower facility in Wyoming, USA and included before and after studies as well as control and treatment sites. The research determined that the number of fatalities at the treatment site declined by 63% between the before and after periods of testing IdentiFlight while fatality numbers increased at the control site by 113%. These estimates are corrected for seasonal and site-specific variation in rates of detection of eagle carcass and rates of removal of carcasses by scavengers.

A close up photo of the IdentiFlight automated curtailment system in front of a wind turbine
The IdentiFlight automated curtailment system

Dr. Chris McClure, Director of Global Conservation Science at The Peregrine Fund and lead author on this study, concludes, “These results show that using the IdentiFlight system can lessen numbers of fatalities of eagles at wind energy facilities, reducing the conflict between wind energy and raptor conservation.”

Dr. Todd Katzner of the U.S. Geological Survey adds, “It is important to note that while this technology significantly reduced eagle collisions, it did not completely eliminate them. Next steps could include partnering this technology with other mitigation actions, such as avoiding construction of turbines in high-risk areas for wildlife conflict.”

Bald Eagles perch in a tree in front of a wind facility in Idaho
Bald Eagles perch in a tree in front of a wind facility in Idaho

“IdentiFlight was excited to see independent verification that our technology protects wildlife and supports power production from renewable sources,” said Carlos Jorquera, chief technology officer for IdentiFlight.  “One of the advantages of the IdentiFlight system is its ability to learn from the massive amounts of data that it collects daily from eagles and other protected bird species around the world.  By leveraging artificial intelligence technologies such as machine-learning and convolutional neural networks, the system continuously improves as the data set grows. We are very excited and confident for IdentiFlight to continue to demonstrate dramatic improvements in its efficacy as we enter the new year.”

“Based on our early evaluation of the IdentiFlight technology, anecdotally we were convinced that it would greatly reduce eagle fatalities at our Top of the World Windpower project in Wyoming. This independent research confirms our earlier predictions and shows how the technology can effectively perform over an extended period of time,” said Tim Hayes, environmental director with Duke Energy Renewables. “It is our mission to reduce impacts to wildlife while generating affordable, clean energy for the communities we serve. IdentiFlight is just one way we support the environment in which our renewable energy projects operate.” 

Dr. McClure says, “As this technology continues to develop and improve, it has the potential to greatly impact raptor conservation around the globe. This is important because we know that more than half of the world’s raptors have declining global populations, and energy infrastructure continues to grow at a rapid rate in places like sub-Saharan Africa where the majority of Endangered and Critically Endangered Vultures are at high risk of collision.”

Eagles fly near wind turbines
White-tailed Eagles fly near wind turbines in Smola, Norway

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