Bat activity, composition, and collision mortality at a large wind plant in Minnesota


  • Gregory D. Johnson,

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    • Gregory D. Johnson (photo) has been an ecologist and project manager for Western EcoSystems Technology, Inc. (WEST) since 1991. He received a B.S. degree in wildlife conservation and management and an M.S. in zoology and physiology from the University of Wyoming. He is a Certified Wildlife Biologist through TWS. Over the last 9 years he has studied wildlife-windpower interactions at proposed or existing wind energy facilities in 12 states, and is currently focusing his research on avian issues associated with a proposed offshore wind park near Long Island, New York and potential effects of wind energy development on endangered bats in the eastern U.S.

  • Matthew K. Perlik,

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    • Matthew K. Perlik is a graduate research assistant at Minnesota State University, Mankato, where he studied bat ecology. He received his B.S. in biology and field biology from Ohio Northern University. He studied European snowshoe hare browsing activity and its impact on silviculture at the University of Joensuu, Finland. His current interests include conservation and restoration of wetland and riparian wildlife habitat.

  • Wallace P. Erickson,

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    • Wallace P. Erickson is a statistician and project manager with WEST with over 10 years of work experience related to the design and analysis of environmental and wildlife studies. He has a B.S. in statistics from Winona State University, an M.S. in biostatistics from the University of Wyoming, and is currently working on a Ph.D. in statistics at the University of Wyoming. His primary research interests include habitat selection methodology with applications to GIS and in study designs and analysis for detecting impacts from environmental perturbations. He has been involved in studies of the impacts of wind plants on wildlife in numerous states.

  • M. Dale Strickland

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    • M. Dale Strickland, Vice President and Senior Ecologist for WEST, received a B.S. in zoology and an M.S. in wildlife management from the University of Tennessee, and a Ph.D. in zoology and physiology from the University of Wyoming. Prior to his employment with WEST, he worked for approximately 16 years with the Wyoming Game and Fish Department. Dr. Strickland is a Certified Wildlife Biologist through TWS and a certified Senior Ecologist through ESA. His current interests are focused on wildlife and energy development issues and issues related to the conservation and management of threatened and endangered species and their habitat. He has studied wildlife-windpower interactions for 12 years and is currently a member of the National Wind Coordination Committee's Wildlife Working Group.

Western EcoSystems Technology, Inc., 2003 Central Avenue, Cheyenne, WY 82001, USA; e-mail for Johnson:

Biological Sciences Department, Minnesota State University Mankato, S-242 Trafton Science Center, Mankato, MN, USA.


We examined bat activity levels, species composition, and collision mortality at a large wind plant in southwest Minnesota from 15 June-15 September, 2001 and 2002. We found 151 bat casualties, most of which were hoary bats (Lasiurus cinereus). We recorded 3,718 bat passes at bat foraging and roosting areas within 3.6 km of the wind plant (x̄=48/detector-night) and 452 bat passes at wind turbines (x̄=1.9/detector-night). Peak bat activity at turbines followed the same trend as bat mortality and occurred from mid-July through the end of August. Based on the timing of fall bat migration, we believe that most bat mortality involved migrating bats. There was no significant relationship between bat activity at turbines or the number of fatalities and presence of lights on turbines. We captured 103 bats comprised of 5 species in mist nets. Big brown bats (Eptesicus fuscus) comprised most of the captures. Our study indicated that there were relatively large breeding populations of bats near the wind plant when collision mortality was low to nonexistent. Future research should concentrate on determining causes of bat collisions and methods to reduce or mitigate the mortality.