Ultrasonic Deterrents To Reduce Bat Mortality at Wind Turbines—Short Science Summary

Bats

In North America, several bat species commonly collide with operating turbines. Although the ultimate cause of collisions is unknown, studies suggest bats may be attracted to turbines because they often approach turbine structures and spend extended periods of time (seconds to minutes) near them. To reduce bat mortality at wind farms, operators seek to reduce the amount of time bats spend near spinning turbine blades (known as exposure). Current approaches to reduce exposure include both curtailment, in which turbine operators stop turbine rotors from spinning during periods when bats are expected to be at the highest risk of collision, and deterrent technologies that seek to discourage bats from entering the rotor-swept area or at least limit the amount of time spent there.

The use of ultrasonic deterrent devices that emit one or more high-frequency sounds has been the most tested technique. The idea behind using ultrasound as a deterrent is it disrupts the ability of bats to effectively echolocate (sometimes referred to as signal jamming). According to this idea, introducing ultrasonic noise in the environment in the same frequency ranges that bats use to echolocate makes it difficult for bats to reliably interpret their own ultrasonic vocalizations. Bats are expected to vacate environments where echolocation is required but becomes unreliable. To test this hypothesis, researchers have investigated the behavioral responses of bats in laboratory (Spanjer 2006) and natural settings (Szewczak and Arnett 2007; Gilmour et al. 2020; Fritts et al. 2024).

In one of the earliest studies on the topic, Szewczak and Arnett (2007) used ultrasonic deterrents at a natural pond that bats frequented for drinking and foraging. Szewczak and Arnett demonstrated that ultrasonic deterrents greatly reduced the overall bat activity rates within a distance of approximately 20 meters (m). Despite relatively consistent results using ultrasound deterrents in natural settings (Szewczak and Arnett 2007; Gilmour et al. 2020) and as a tool to discourage bats (at least temporarily) from approaching buildings and bridges (Zeale et al. 2016; Aldemir Bektas et al. 2022), researchers’ ability to reduce bat mortality rates around wind turbines has been inconsistent (Table 1). For example, Weaver et al. (2020) found that ultrasonic deterrents reduced hoary bat (Lasiurus cinereus) and Brazilian free-tailed bat (Tadarida brasiliensis) fatalities but found no difference in the number of northern yellow bat (Lasiurus intermedius) carcasses between turbines with and without ultrasonic deterrents. Despite overall reductions in bat fatalities, several studies reported increased fatalities when considering species-specific effects.

The table below contains the literature relevant to this summary document and will continue to be updated as new literature is added to Tethys.

Title Author Date Content Type Technology Stressor Receptor
Temporal Patterns in Capture Rate and Sex Ratio of Forest Bats in Arkansas Perry, R., Carter, S., Thill, R. Journal Article Wind Energy, Land-Based Wind Collision Bats
Klondike III (Phase 1) Wind Power Project Wildlife Monitoring Study October 2007–October 2009 Gritski, B., Downes, S., Kronner, K. Report Wind Energy, Land-Based Wind Collision Bats, Birds
Post-Construction Avian Monitoring Study for the Shiloh II Wind Power Project Solano County, California Kerlinger, P., Curry, R., Culp, L., Hasch, A., Jain, A. Report Wind Energy, Land-Based Wind Collision Bats, Birds
Bat Mortality at Wind Turbines in Northwestern Europe Rydell, J., Bach, L., Dubourg-Savage, M., Green, M., Rodrigues, L., Hedenstrom, A. Journal Article Wind Energy, Land-Based Wind Collision Bats
Search Areas for Monitoring Bird and Bat Carcasses at Wind Farms using a Monte-Carlo Model Hull, C., Muir, S. Journal Article Wind Energy, Land-Based Wind Collision Bats, Birds
Effectiveness of Changing Wind Turbine Cut-in Speed to Reduce Bat Fatalities at Wind Facilities 2010 Arnett, E., Schirmacher, M., Huso, M., Hayes, J. Report Wind Energy, Land-Based Wind Collision Bats
Spatial Pattern of Summer Bat Mortality from Collisions with Wind Turbines in Mixed-Grass Prairie Piorkowski, M., O'Connell, T. Journal Article Wind Energy, Land-Based Wind Collision Birds, Bats
Bats are not birds and other problems with Sovacool's (2009) analysis of animal fatalities due to electricity generation Willis, C., Barclay, R., Boyles, J., Brigham, R., Brack, V., Waldien, D., Reichard, J. Journal Article Wind Energy, Land-Based Wind Displacement, Collision, Attraction Birds, Bats
Avian, bat and habitat cumulative impacts associated with wind energy development in the Columbia Plateau Ecoregion of Eastern Washington and Oregon Johnson, G., Erickson, W. Report Wind Energy, Land-Based Wind Collision, Habitat Change Bats, Birds
Best Management Practices for Bats in New Mexico Balistreri, M. Report Wind Energy, Land-Based Wind Attraction, Avoidance, Collision, Habitat Change Bats
Post‐Construction Bat and Bird Fatality Study at the Blue Sky Green Field Wind Energy Center, Fond du Lac County, Wisconsin: July 21, 2008 – October 31, 2008 and March 15, 2009 – June 4, 2009 Gruver, J., Sonnenburg, M., Bay, K., Erickson, W. Report Wind Energy, Land-Based Wind Collision Birds, Bats
Bats on the move Popa-Lisseanu, A., Voigt, C. Journal Article Wind Energy, Land-Based Wind Collision Bats, Birds
Geographic Variation in Activity and Fatality of Migratory Bats at Wind Energy Facilities Baerwald, E., Barclay, R. Journal Article Wind Energy, Land-Based Wind Collision Bats
Ripley Wind Power Project Post-Construction Monitoring Report Jacques Whitford Stantec Limited Report Wind Energy, Land-Based Wind Collision Bats, Birds
2008/2009 Annual Report for the Buena Vista Avian and Bat Monitoring Project Insignia Environmental Report Wind Energy, Land-Based Wind Collision Bats, Birds
Avian and Bat Fatality Rates at Old-Generation and Repowered Wind Turbines in California Smallwood, K., Karas, B. Journal Article Wind Energy, Land-Based Wind Collision Raptors, Birds, Bats
A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities Baerwald, E., Edworthy, J., Holder, M., Barclay, R. Journal Article Wind Energy, Land-Based Wind Collision Bats
The Aversive Effect of Electromagnetic Radiation on Foraging Bats—A Possible Means of Discouraging Bats from Approaching Wind Turbines Nicholls, B., Racey, P. Journal Article Wind Energy, Land-Based Wind Collision, EMF Bats
Interim Report: Post-Construction Bat and Bird Fatality Study Blue Sky Green Field Wind Resource Area Fond du Lac County, Wisconsin Gruver, J., Bay, K., Erickson, W. Report Wind Energy, Land-Based Wind Collision Bats, Birds
Bats and Onshore Wind Farms: Site-by-Site Assessment and Post-Construction Monitoring Protocols Catherine, C., Spray, S. Magazine Article Wind Energy, Land-Based Wind Collision Bats
Proceedings of the Wind Wildlife Research Meeting VII Schwartz, S. Conference Paper Wind Energy, Land-Based Wind, Fixed Offshore Wind Collision, Habitat Change Bats, Birds
Patterns of Bat Fatality at the Casselman Wind Project in South-Central Pennsylvania: 2008 Annual Report Arnett, E., Schirmacher, M., Huso, M., Hayes, J. Report Wind Energy, Land-Based Wind Collision Bats
Birds, Bats and Coastal Wind Farm Development in Maine: A Literature Review Goodale, W., Divoll, T. Report Wind Energy, Land-Based Wind Collision, Habitat Change Bats, Birds
Annual Report for the Maple Ridge Wind Power Project Postconstruction Bird and Bat Fatality Study - 2007 Jain, A., Kerlinger, P., Curry, R., Slobodnik, L. Report Wind Energy, Land-Based Wind Collision Bats, Birds, Ground-Nesting Birds, Passerines, Raptors, Shorebirds, Waterfowl
On-Shore Bird and Bat Pre- and Post-Construction Monitoring Protocol for Commercial Wind Energy Facilities in Ohio: An Addendum to the Ohio Department of Natural Resources Voluntary Cooperative Agreement Ohio Department of Natural Resources Report Wind Energy, Land-Based Wind Collision, Habitat Change Bats, Birds
Annual Report for the Noble Bliss Windpark, LLC Postconstruction Bird and Bat Fatality Study 2008 Jain, A., Kerlinger, P., Curry, R., Slobodnik, L., Quant, J., Pursell, D. Report Wind Energy, Land-Based Wind Collision Bats, Birds
Effectiveness of Changing Wind Turbine Cut-in Speed to Reduce Bat Fatalities at Wind Facilities 2009 Arnett, E., Schirmacher, M., Huso, M., Hayes, J. Report Wind Energy, Land-Based Wind Collision Bats
Chiropteran Risk Assessment: Proposed Pleasant Ridge Wind Energy Generation Facility, Livingston County, Illinois BHE Environmental Inc Report Wind Energy, Land-Based Wind Collision Bats
Avian and Bat Protection Plan: Iberdrola Renewables Iberdrola Renewables Report Wind Energy, Land-Based Wind Avoidance, Collision, Displacement, Habitat Change Bats, Birds, Raptors
How Ecofriendly are Wind Farms? Cohn, J. Journal Article Wind Energy, Land-Based Wind Collision, Avoidance, Attraction Raptors, Birds, Bats
Testing the Effectiveness of an Experimental Acoustic Bat Deterrent at the Maple Ridge Wind Farm Horn, J., Arnett, E., Jensen, M., Kunz, T. Report Wind Energy, Land-Based Wind Avoidance, Collision Bats
Wind Power Company Compliance with Mitigation Plans in the Altamont Pass Wind Resource Area Smallwood, K. Journal Article Wind Energy, Land-Based Wind Habitat Change, Collision Birds, Bats
Mating Behavior as a Possible Cause of Bat Fatalities at Wind Turbines Cryan, P. Journal Article Wind Energy, Land-Based Wind Attraction, Collision Bats
Behavioral Responses of Bats to Operating Wind Turbines Horn, J., Arnett, E., Kunz, T. Journal Article Wind Energy, Land-Based Wind Attraction, Avoidance, Collision Bats
Patterns of Bat Fatalities at Wind Energy Facilities in North America Arnett, E., Brown, W., Erickson, W., Fiedler, J., Hamiltons, B., Henry, T., Jain, A., Johnson, G., Kerns, J., Koford, R., Nicholson, C., O'Connell, T., Piorkowski, M., Tankersley, R. Jr. Journal Article Wind Energy, Land-Based Wind Collision Bats
Probability of Impact Workshop National Wind Coordinating Collaborative Report Wind Energy, Land-Based Wind, Fixed Offshore Wind Collision, Habitat Change Bats, Birds
Prairie Winds: Migrating Bats & Wind Energy in Canada Baerwald, E. Magazine Article Wind Energy, Land-Based Wind Collision Bats
Ecological Impacts of Wind Energy Development on Bats: Questions, Research Needs, and Hypotheses Kunz, T., Arnett, E., Erickson, W., Hoar, A., Johnson, G., Larkin, R., Stickland, M., Thresher, R., Tuttle, M. Journal Article Wind Energy, Land-Based Wind Attraction, Avoidance, Collision, Displacement Bats
Results of Bat and Bird Mortality Monitoring at the Expanded Buffalo Mountain Windfarm, 2005 Fiedler, J., Henry, T., Tankersley, R. Jr., Nicholson, C. Report Wind Energy, Land-Based Wind Collision Passerines, Birds, Bats
Biglow Canyon Wind Farm: Wildlife Monitoring and Mitigation Plan Portland General Electric Company, Oregon Department of Energy Report Wind Energy, Land-Based Wind Collision, Habitat Change Bats, Birds, Raptors
Displaying 281 - 320 of 348 results