A Review of Options for Mitigating Take of Golden Eagles at Wind Energy Facilities.

Wind energy development has expanded rapidly in the past decade, becoming a significant source of electricity, and a major element in a global strategy to reduce carbon emissions and the effects of climate change. Golden Eagles ( Aquila chrysaetos) can collide with wind turbines, adding to the existing and substantial mortality from other anthropogenic sources. These collisions are a conservation concern, and they pose a legal risk to wind energy companies and potentially hamper development in areas where the range of Golden Eagle overlaps areas of high wind energy potential. The U.S. Fish and Wildlife Service, through the revised Eagle Rule and the Eagle Conservation Plan Guidance, has designed a mitigation strategy for eagle conservation that allows wind energy companies to obtain incidental take permits. However, the strategy is challenged by a lack of data supporting scientifically rigorous strategies to mitigate eagle take, where mitigation is defined as efforts to avoid and minimize take, and compensate for unavoidable take. We review the steps and options a wind developer can consider to mitigate predicted eagle collisions with wind turbines consistent with the U.S. Fish and Wildlife Service's revised Eagle Rule and Eagle Conservation Plan Guidance. Most of these options have limited or no scientific support and their effect on reducing risk of eagle collisions is unknown. We briefly describe approaches for evaluating technology intended to minimize eagle take and for developing options to offset unavoidable eagle take that are quantifiable and verifiable. Because estimates of Golden Eagle fatalities at many wind energy projects are low, research to evaluate mitigation measures needs to be coordinated and collaborative across multiple wind energy facilities to improve our ability to produce scientifically robust mitigation strategies. The impetus for these efforts is improving implementation and compliance with the revised Eagle Rule, but the results have benefits beyond Golden Eagles, for raptors and their ecological communities.