Effectiveness of Acoustic Lures for Increasing Indiana Bat Captures in Mist-Nets

As bat (Chiroptera) populations continue to decline in the eastern United States due to threats such as white-nose syndrome and interactions with wind facilities, capturing already rare species such as the federally endangered Indiana bat Myotis sodalis to assess health and demographics has become increasingly difficult. Mist-nets are a standard method for capturing and studying bats, but bats have the ability to escape from or avoid mist-nets. Past research has shown that the use of acoustic lures may increase mist-net capture success. Using prerecorded Indiana bat social calls, we tested the effectiveness of acoustic lures on capture rates across 24 nights at 37 sites in summers 2013 and 2014 in north-central Kentucky. Each site consisted of two nets (treatment and control) placed >35 m apart: we placed an acoustic lure set 1 m in front of the treatment net, whereas the control net received no lure. At the species level, we recorded significantly more captures in treatment nets (n = 262) than in control nets [n = 128; t(36) = 5.08, P < 0.001]. However, although we found a trend toward higher Indiana bat captures, the only species' with significant positive responses were evening bats Nycticeius humeralis [t(15) = 6.25, P < 0.001] and eastern red bats Lasiurus borealis [t(36) = 3.60, P < 0.001]. Further study is required to determine whether modifications to lure settings or call types result in increased Indiana bat captures.