Although concerns about the environmental impact of wind energy have historically considered bird fatalities, recent studies have shifted the focus to bats (Johnson et al. 2003, 2004, Kunz et al. 2007, Arnett et al. 2008). Relatively high numbers of bat fatalities have been reported at some wind energy facilities in various landscapes globally (Ahlén 2003, Johnson et al. 2003, Dürr and Bach 2004, Joh n son 20 05, Arnett et al. 2008). In North America, fatality rates vary across the continent, with reports of fatality rates as high as 63.9 bats per turbine per year (Fiedler et al. 2007). Primarily, three species of migratory, tree-roosting bats appear to be affected: hoary bats (Lasiurus cinereus), silver-haired bats (Lasionycteris noctivagans), and eastern red bats (Lasiurus borealis) (Johnson 2005, Arnett et al. 2008). The majority of these fatalities occur during fall migration (mid-July through September) (Arnett et al. 2008).
The published literature on post-construction fatality monitoring at wind energy facilities contains little information on the occurrence of live and injured bats. Between 2001 and 2004, in reports with documented live-bat occurrences, live-bat discovery rates varied between 0.6% (Arnett 2005) and 4.0% (Fiedler 2004). Discovery of live bats on the ground at wind turbines can be frequent; in 2004, researchers found 9 live bats within a 6-wk period at a single site (Arnett 2005). Currently, no published information or guidelines are available that specifically pertain to the documentation and management of live and injured bats found at wind energy facilities.
During our study on patterns and causes of bat fatalities at wind energy facilities, we found numerous live and injured bats. In this paper, we examine patterns oflive-bat occurrences at our study site and suggest methods for conducting searches at wind energy facilities to increase the likelihood of finding live bats. We also discuss field methods used to evaluate and manage live and injured bats for successful release or humane euthanization. Traumas sustained by bats from encounters with wind turbines are potentially unique and complex (e.g., Baerwald et al. 2008), and seriously injured bats should be euthanized. Several methods exist to euthanize a bat and we discuss those we employed in the field.