Bat mortality at a wind‐energy facility in southeastern Wisconsin

Abstract

AbstractThe wind‐energy industry is rapidly developing worldwide as a viable renewable power option to offset high economic and environmental costs of fossil fuel consumption and nuclear power generation. Evidence suggests bats are more likely to be negatively affected by wind facilities than are birds. Studies have shown that significant bat mortality occurs at wind facilities, yet our understanding of the concomitant drivers of these events is limited. Our objectives were to assess the impact of a wind facility in southeastern Wisconsin, USA, on migratory and non‐migratory and/or short‐distance migrant bats by 1) estimating mortality, 2) recording species composition of mortality cases, and 3) determining the correlative variables associated with bat mortality events. We estimated 4,454 total bats, 3,019 migratory and 912 non‐migratory and/or short‐distance migrant bats were killed, respectively, over 277 search days during two spring and two autumn study periods, 2008–2010. We found bat mortality was strongly linked to migration. Approximately one‐quarter of all bat mortality consisted of non‐migratory big brown bats (Eptesicus fuscus) and short‐distance migrant little brown bats (Myotis lucifugus), which is higher than many previous studies, supported by similar studies in the Midwest, and of concern due to these species' susceptibility to white‐nose syndrome. We determined weanling mice were suitable surrogates for bat carcasses in scavenger removal trials. We found temperature was positively related to bat mortality, which indicates a possible link with prey availability. We encourage standardization in search and statistical methods across studies and acknowledgment of migratory and non‐migratory and/or short‐distance migrant bat mortality at wind facilities in agricultural landscapes. © 2012 The Wildlife Society.