Image of volunteer using a bat detector

Acoustic Bat Monitoring

Bats in Wisconsin use echolocation to navigate and hunt. Bat echolocation is in the ultrasonic range which means it is above human hearing. How bats can fly in complete darkness remained a mystery until the 1930s when scientists discovered that bats use echolocation. Special ultrasonic detection equipment was developed and opened a whole new method for studying bats.

To conduct acoustic bat surveys in Wisconsin, volunteers are trained to use handheld ultrasonic detectors, or bat detectors as they are affectionately called. The system consists of a detector that records the ultrasound, a PDA that displays the bat calls on a graph of frequecy over time, and a GPS unit that tracks the route taken and pinpoints each bat call. Data is saved onto the PDA and analyzed in the office. Just like birds, bat species have different calls from each other. By looking at the frequency, shape and other characteristics of calls, the WBP can identify the species of bat that was recorded.

There are three types of acoustic surveys you can do: land, water and driving. Find a regional coordinator below to learn how to conduct acoustic bat surveys.You can also check out our 2015 Acoustic Bat Monitoring Report to learn more about past efforts.

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Map of detector locations by county

Check out a legend of the species and results from past surveys.

Map results of a completed water survey
Results of a water survey completed on Sugar River



This site is produced in conjunction with the Wisconsin Aquatic and Terrestrial Resources Inventory and sponsored by the Wisconsin Department of Natural Resources. The information presented on this site is subject to the Wisconsin Department of Natural Resources' Legal Notices, Disclaimers, and Terms of Use.