The North American Bat (NABat) Monitoring Program is a research protocol that monitors bats across large landscapes. The Nebraska North American Bat Monitoring Program used the protocol to increase our understanding of bat populations and habitat use, which promoted the long-term viability of bat populations across Nebraska and North America.
There are 13 bat species found in the state. Nebraska is particularly interesting since it is situated where Eastern and Western bat species overlap in the United States. Bats are considered important species to ecosystems since they are influential in controlling insect populations. However, because bats have long lifespans (30+ years) and usually a breeding pair only has one young per year, bat populations are especially vulnerable to decline due to threats such as habitat destruction.
CRAWL established 127 sampling locations and nearly 870 miles of transect survey routes across the state.
Using Sound for Research
All Nebraska bats use echolocation to find prey and avoid obstacles in the dark. Bats bounce high-frequency ultrasound off their surroundings and listen to the response to navigate and eat insects in total darkness. We used sensitive “Ultrasound Acoustic Detectors” to record the ultrasound that bats emit. Since each species of bat emits a unique pattern and call shape, we were able to use computer analysis to identify which bats were in the area.
Study Methods
- Stationary Sound Detectors
- We placed Ultrasound Acoustic Detectors at stationary points on public and private land. These detectors passively recorded bat echolocation from dusk till dawn for 4 to 6 days.
- We took detailed site measurements around each detector to record the habitat characteristics that may influence bat presence.
- Car-based Driving Transects
- An Ultrasound Acoustic Detector was attached to the roof of a vehicle.
- After sunset, we drove a 15- to 30-mile transect at 20 mph on the roads near stationary detectors.
- Since we drove faster than bats can fly, we assumed that each bat detected is a unique individual. This gives us a view into the bat population of Nebraska.
