Wind farms have received heat in recent years for their potential to harm wildlife, a notable issue in western North America where some farms are located near populations of protected Bald Eagles ( Haliaeetus leucocephalus ) and Golden Eagles ( Aquila chrysaetos ). A new study published in the Journal of Raptor Research titled “Behavioral Responses of Large Soaring Raptors to Audio Deterrents at Commercial Wind-Energy Facilities in the Western USA” found that outfitting turbines with devices that emit warning sounds to approaching raptors can effectively reduce the number of collisions, and therefore deaths, at wind energy sites. For large soaring birds like eagles, hawks, and vultures, this is an especially valuable finding and offers a positive development for a long-standing conservation challenge.
As efforts to reduce global carbon footprints ramp up, so do concerns about the effects of renewable energy on wildlife populations. The turbines used to generate power at wind farms pose a documented risk to large soaring raptors, as both the birds and the turbine operations thrive in windy places. A bird that enters the “rotor-swept zone” (RSZ), the most dangerous radius around the turbine, has a low chance of exiting unscathed. Many raptors have limited sensory ability to detect the turbines in time to avoid them. Wind farms must comply with the Bald and Golden Eagle Protection Act, however, which creates impetus for companies to help eagles avoid the turbines in the first place.
A research team from H.T. Harvey & Associates (recently merged with Integral Consulting Inc.), working in collaboration with the Renewable Energy Wildlife Institute, set up DTBird audio deterrents at two different wind farms: the Manzana Wind Power Project in southern California and the Goodnoe Hills Wind Farm in south-central Washington. When an eagle or hawk-sized raptor approached a turbine, the deterrent system emitted one or both of two sounds — first a warning “whistle-whoop” signal to attract the bird’s attention and then, if warranted, a louder and more raucous “dissuasion signal” to discourage a closer approach. Wildlife technicians then reviewed video clips to classify the birds’ behavioral responses to determine how well the system worked in preventing collisions.
At both wind farms, the deterrents dissuaded approaching raptors more than 50% of the time, across species, which included Golden Eagles, Bald Eagles, Turkey Vultures ( Cathartes aura ), and various hawk species. The higher the winds, the more responsive the larger species were towards the deterrents, potentially because faster-spinning turbine blades are inherently more noticeable to the birds as they approach, and the combined effect may have kept the birds from entering the RSZ. Larger species may also be more agile in higher wind speeds and thus more able to maneuver away from the blades. Interestingly, the team hypothesized that birds at lower risk of collision, meaning those already headed for a safer route around the turbines, would be less likely to respond to the deterrents. This proved to be true, however birds at the highest risk of collision did not necessarily respond most effectively, probably because they could not implement an effective avoidance response in a timely fashion.
This study is the first to evaluate the effectiveness of audio deterrents placed at wind farms in North America. Lead authors Jeff Smith and Shilo Felton are optimistic about the findings, saying “products like this provide a solution to reduce negative impacts to raptors from wind energy development to create a win-win for raptor conservation.” The team’s motivation was to improve the available technology and provide critical information on the effectiveness of the DTBird system. “This study, supported by the U.S Department of Energy, gives the U.S. Fish and Wildlife Service evidence-based information to consider in federal policy decisions,” says Dr. Felton. They hope further research will focus on evaluating the effectiveness of the DTBird system across spatial scales and at different facilities. Raptors are top predators, meaning they exert a strong influence on the health of their food web. Without them, overall ecosystem health suffers. As myriad forms of development continue to alter the landscape on which these raptors thrive, studies that highlight mitigation opportunities will become more useful for the companies required to protect the species they could displace. This study, and others like it, are instrumental in fine-tuning this process.
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Paper:
Smith, Jeff P., et al. (2026). Behavioral Responses of Large Soaring Raptors to Audio Deterrents at Commercial Wind-Energy Facilities in the Western USA. Journal of Raptor Research, 60(3 ):1–19. DOI: 10.3356/jrr2516
Notes to Editor:
1. The Journal of Raptor Research (JRR) is an international scientific journal dedicated entirely to the dissemination of information about birds of prey. Established in 1967, JRR has published peer-reviewed research on raptor ecology, behavior, life history, conservation, and techniques. JRR is available quarterly to members in electronic and paper format.
2. The Raptor Research Foundation (RRF) is the world’s largest professional society for raptor researchers and conservationists. Founded in 1966 as a non-profit organization, our primary goal is the accumulation and dissemination of scientific information about raptors. The Foundation organizes annual scientific conferences and provides competitive grants and awards for student researchers and conservationists. The Foundation also provides support and networking opportunities for students and early career raptor researchers.
Journal of Raptor Research
Data/statistical analysis
Animals
Behavioral Responses of Large Soaring Raptors to Audio Deterrents at Commercial Wind-Energy Facilities in the Western USA
20-Aug-2026