Testing the effectiveness of an experimental bat deterrent at the Maple Ridge Wind farm.

  • Published source details Horn J.W., Arnett E.B., Jensen M. & Kunz T.H. (2008) Testing the effectiveness of an experimental bat deterrent at the Maple Ridge Wind farm. Bat Conservation International report.


This study is summarised as evidence for the following.

Action Category

Deter bats from turbines using ultrasound

Action Link
Bat Conservation
  1. Deter bats from turbines using ultrasound

    A paired sites study in 2007 on a wind farm in an agricultural area of New York, USA (Horn et al. 2008) found mixed effects on bat activity during two trials with an ultrasonic deterrent, and the deterrent did not have a significant effect overall. Fewer bats were observed over 10 consecutive nights at a turbine with an ultrasonic deterrent fitted (average 13 bat passes/night) than at a matched control turbine without a deterrent (average 24 bat passes/night). No significant difference was found in bat activity when this was repeated with a second matched pair (average 10 bat passes/night at both). The ultrasonic deterrent did not have a significant effect on the number of bats observed when results from both trials were combined (data reported as statistical model results). The deterrent broadcast random pulses of broadband ultrasound from 20–80 kHz. For both trials, bat activity was observed simultaneously at treatment and control turbines for 3.6 h after sunset for 10 consecutive nights in August 2007 using thermal infrared imaging cameras. Bats were not identified to species.

    (Summarised by: Anna Berthinussen)

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