As wind energy expands to meet emissions reduction goals, so do proposed options to conserve golden eagles, raising the question: What is the best strategy for evaluating and implementing such conservation measures? A new report co-authored by AWWI Director of Research Dr. Taber Allison, “A Review of Options for Mitigating Take of Golden Eagles at Wind Energy Facilities” in The Journal of Raptor Research, points the way forward and provides an updated framework for AWWI’s Eagle Program.
“The review suggests that by expanding the number of verified, scientifically-sound strategies for avoiding, minimizing, and offsetting eagle take we can develop wind energy and conserve eagles,” said Taber. “To advance and implement solutions, we need effective coordination among scientists, wildlife agencies, and the wind energy industry.”
Golden eagles have a wide range and there is some risk for collision with wind turbines in areas where their range overlaps with wind energy development. While bald eagles have seen populations rebound since the banning of DDT, golden eagles still experience substantial anthropogenic mortality from shooting, electrocution, poisoning, and other sources. Although estimates of golden eagle fatalities at many wind energy facilities are low, any fatalities resulting from collisions with wind turbines add to the conservation concern about this species due to the other threats they face.
The study reviews the options that currently exist for eagle mitigation. The U.S. Fish and Wildlife Service (USFWS) has based the conservation strategy of its revised Eagle Rule on requirements to predict and avoid, minimize, and offset unavoidable harm, or “take” of eagles. The review shows that while many options exist in practice, few are scientifically verified and approved for use in permits.
According to the review:
- To predict risk and avoid take (for example, through siting of wind energy facilities), a predictive model has been developed by the USFWS, but its accuracy has not been verified. Wind energy companies may therefore be under- or over-predicting risk, and additional data are needed to refine the model’s accuracy.
- To minimize take, the USFWS has approved siting as a mitigation measure (e.g., reduction in number of turbines or change in the siting of individual turbines). Other steps have been proposed to minimize take, such as combining detection of eagles with temporary shut-down of wind turbines or with deterrence systems. As more wind energy projects enter operation, there are more opportunities to rigorously evaluate the effectiveness of proposed measures on a before-and-after basis. Such research will be more effective if coordinated across facilities. Overall, there are few currently approved mitigation measures.
- Currently, retrofitting transmission line power poles is the method available to companies for offsetting take of golden eagles. Additional mitigation options have been proposed, such as reducing lead poisoning in eagles through voluntary programs to avoid lead ammunition, or removing roadkill to reduce eagle vehicle strikes. As these and other options are proposed, data will help quantify results and verify accuracy. Meanwhile, researchers have developed a general approach to model the effectiveness of mitigation options based on eagle and other expert input, and this scientific “expert elicitation” modeling should help accelerate adoption of these measures.
The review concludes that continued research and coordination in the field with an eye on effective implementation are the way forward. AWWI, the Bat and Wind Energy Cooperative (BWEC), and the National Wind Coordinating Collaborative (NWCC – facilitated by AWWI), are cited as examples of this collaborative and coordinated approach.
“AWWI, with the National Research Plan and a balanced, collaborative partnership structure that brings together wind energy companies, fish and wildlife agencies, and scientific and conservation organizations is indeed already catalyzing efforts,” said AWWI Executive Director Abby Arnold. “We have the ability to effectively address these challenges if we continue to work together, and, thanks to its collaborative nature, AWWI is already advancing effective solutions.”
AWWI’s Eagle Program will develop and evaluate potential best management practices for avoiding and minimizing eagle take, including through verification of detection and deterrent technologies, in addition to developing and supporting the implementation of compensatory mitigation strategies. Learn more about AWWI’s eagle research and resources here.
Review Authors: Taber D. Allison, Jean Fitts Cochrane, Eric Lonsdorf, Carol Sanders-Reed