Acoustic Bat Monitoring
High-tech and hands-off: New tools allow for rapid bat surveys statewide.
Zoom+ AnaBat acoustic detector. The attached PDA (like a little computer screen) lets us view incoming bat calls instantly. © MacKenzie Hall
Echolocation
In early 2010, the Conserve Wildlife Foundation purchased two AnaBat acoustic detectors to aid in bat research across the state. Acoustic detectors take advantage of a key bat behavior: echolocation. As bats fly, they are constantly giving off rapid, high-frequency pulses of sound (or “calls”). The sound pulses bounce off nearby objects and return to the bats’ ears as echoes, providing them with feedback about the size, shape, distance, and trajectory of those objects. Thus bats can navigate through the forest, avoid obstacles, swoop down for a drink of water, and hunt for insects in the total darkness of night.
Zoom+ Captured by AnaBat: Examples of the call patterns made by four different bat species (eastern red bat, hoary bat, little brown bat, and tri-colored bat, from top left to bottom).
Acoustic Detection
For the most part, bat calls are ultrasonic – meaning they’re above the 20 kHz upper range of human hearing. So we can’t hear them…but an acoustic detector can. The AnaBat’s sensitive microphone can detect bats from up to 300 feet away, and a memory chip stores each bat call for later analysis. Since different bat species have unique call patterns that can be used to tell them apart, acoustic technology allows you to document the diversity as well as the abundance of bats in an area of interest.
With bats facing new and serious threats – like White-Nose Syndrome and the rise of wind turbines – there is an urgent need for bat population data. In the Northeast, several states are now including acoustic surveys in their toolkit. Detectors can be mounted on vehicles and activated while driving at night, making them a pretty quick and easy way to get a lot of information…all without having to catch, hold, or even see a single animal.
Zoom+ Erica Fischer (summer 2011 intern) mounts an AnaBat detector to the roof of a vehicle and waits for dusk. Jim Wright, N.J. Meadowlands Commission
Want to Volunteer?
We have begun inviting volunteers to help with mobile acoustic surveys. Volunteers are assigned a 10-30 mile driving route in their local area to travel at least once each summer after dark. Volunteers must be familiar with electronics and be able to follow specific instructions. In 2011, we completed 50 mobile acoustic surveys statewide. Let us know if you’d like to help!
Acoustic Survey Materials:
 | Mobile Acoustic Bat Survey Instructions - 69.9KB |
| Acoustic Transect Data Sheet - 18.3KB |
Contact Us:
MacKenzie Hall, Private Lands Biologist: Email
908.782.4614, Ext. 104
Find Related Info: Bats
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