Use of Innovative Technology to Deter Bat Bridge Use Prior to and During Construction

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White-Nose Syndrome and increased disturbance of habitats used by bats for roosting and foraging has led to a growing concern about the U.S. bat population over the last decade. Bridge repair and replacement projects are required to follow additional regulatory requirements to avoid and minimize impacts to bats; when protected bat species are present on bridges. Some of these requirements (e.g.; timing restrictions) are challenging to implement given Minnesota's short construction season. The objective of this project was to evaluate the feasibility and efficacy of deploying non-lethal ultrasonic acoustic devices in the field to temporarily deter bats from roosting on bridges ahead of construction or maintenance activities; while minimizing harm to bats and non-target species. The technology was evaluated at two test sites in Minnesota; one short-term and one long-term; during the summer of 2019. Considering the findings from both the acoustic monitoring data and the field inspections; acoustic deterrents appeared to effectively work to temporarily deter bats from select abutments. This report presents the field study design; findings from the field implementation; research benefits; and implementation steps for the Minnesota Department of Transportation (MnDOT).