Evaluation of an acoustic deterrent to reduce bat mortalities at an Illinois wind farm

Published source details Romano W.B., Skalski J.R., Townsend R.L., Kinzie K.W., Coppinger K.D. & Miller M.F. (2019) Evaluation of an acoustic deterrent to reduce bat mortalities at an Illinois wind farm. Wildlife Society Bulletin, 43, 608-618.
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This study is summarised as evidence for the following.

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	Deter bats from turbines using ultrasound Action Link

Deter bats from turbines using ultrasound

A replicated, randomized, controlled study in 2014–2016 at a wind farm in a forested area of Illinois, USA (Romano et al 2019) found that turbines with ultrasonic deterrents emitting a constant or pulsed signal had mixed effects on bat mortality. Turbines with ultrasonic deterrents emitting a constant signal had 26–36% fewer hoary bat Lasiurus cinereus fatalities compared to turbines with no deterrent (data reported as statistical model results). For silver-haired bats Lasionycteris noctivagans and eastern red bats Lasiurus borealis, there were significantly fewer fatalities (57% and 39% respectively) during one of two years of the study with the constant signal deterrent. Turbines with deterrents emitting a pulsed signal had 73% fewer fatalities of silver-haired bats, but the difference was not significant for hoary bats or eastern red bats. Five other bat species or species groups were identified during carcass searches, although numbers were too low for statistical analysis (see original paper for data). In each of three years, nine or 10 six-day trials were carried out at 12–16 randomly selected turbines (half with deterrents fitted). Deterrents were switched between turbines halfway through each trial. Air-jet ultrasonic deterrents emitted sounds at 30–100 kHz between 1800 and 0630 h. Constant signals were used in 2014 and 2015 and pulsed signals in 2016 (5–8 second duration at 3 second intervals). Transects within a 60-m radius around each turbine were searched daily for bat carcasses during each trial in August–October 2014–2016. Carcass counts were adjusted to account for searcher efficiency and removal by scavengers.

(Summarised by: Anna Berthinussen)