Twenty one bat species have been killed at wind-energy facilities in North America. Migratory tree- and foliage-roosting bats usually are killed most frequently; these include the eastern red bat, hoary bat and silver-haired bat.
Tri-colored bats, little brown myotis and big brown bats also are frequent victims of wind facilities. In the eastern United States, tri-colored bats often represent one-quarter of the fatalities at wind facilities. In some facilities in the upper Midwest, up to 50 percent of bat kills have been big brown bats and little brown myotis.
Within their range in Texas, Oklahoma, and Southwestern states, Mexican free-tailed bats have accounted for large proportions (up to 95 percent) of bat fatalities at some wind facilities. This raises concerns about the potential impact on large maternity colonies in Texas and throughout the Southwest.
To date, two federally endangered species are known to have been killed at a wind facility; the Hawaiian hoary bat and the Indiana myotis. But given the difficulty of finding carcasses, which are often quickly removed by scavengers, it is reasonable to assume that more of these bats have been killed by turbines. Fatalities among endangered species such as the Indiana myotis are likely to increase in the future, given the rapid and broad expansion of wind energy across the range of several endangered bats.
Photos © Merlin D. Tuttle, BCI