Evaluating the effectiveness of an ultrasonic acoustic deterrent for reducing bat fatalities at wind turbines

  • Published source details Arnett E.B., Hein C.D., Schirmacher M.R., Huso M.M.P. & Szewczak J.M. (2013) Evaluating the effectiveness of an ultrasonic acoustic deterrent for reducing bat fatalities at wind turbines. PLoS ONE, 8, e65794.


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 replicated, randomized, controlled study in 2009–2010, with a before-and-after trial in the second year, at a wind farm in a forested area of Pennsylvania, USA (Arnett et al. 2013) found that an ultrasonic deterrent had mixed effects on bat mortality. In 2009, 21–51% fewer bats overall were killed per deterrent turbine (average 6 bats killed/turbine) than control turbine (average 9 bats killed/turbine). The difference in mortality was significant for hoary bats Lasiurus cinereus (deterrent: average 4 bats killed/turbine; control: 2 bats killed/turbine), but not for five other bat species (see original paper for data). In the 2010 before-and-after trial, between 2% more and 64% fewer bats were killed overall at deterrent turbines than at control turbines when accounting for differences found between control and deterrent turbines in the ‘before’ trial. Differences for individual species were not tested for statistical significance due to low numbers (see original paper for data). In 2009 and 2010, 10 randomly selected wind turbines were fitted with deterrent devices, and 15 randomly selected turbines without the device were used as controls. The deterrent emitted continuous ultrasonic broadband noise at 20–100 kHz. In 2009, daily carcass searches were conducted in August–October. In 2010, the before-and-after trial was conducted with daily carcass searches in May–July before the deterrent was used, followed by daily searches in July–October with the deterrent active. Carcass counts were adjusted to account for searcher efficiency and removal by scavengers.

    (Summarised by: Anna Berthinussen)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust