Bat Acoustic Monitoring at Agate Fossil Beds National Monument

a bat rests upside-down on a tree trunk
Silver haired bats (Lasionycteris noctivagans) were one of the most commonly recorded species at Agate Fossil Beds National Monument during monitoring.



Agate Fossil Beds National Monument safeguards Miocene Epoch mammal fossils and the prairie ecosystem in western Nebraska. The Niobrara River is stream-like as it passes through the center of the 3,058 acre park and, although the primary habitat found at Agate Fossil Beds National Monument is Northern Great Plains mixed-grass prairie, there are small groves of old cottonwoods in the floodplain of the Niobrara River that provide good roosting and foraging habitat for bats.

The Northern Great Plains Inventory & Monitoring Network monitors bats to detect long-term trends and to get early warning of undesirable changes in bat populations at the park. A fungal disease called white-nose syndrome is spreading quickly, threatening bat populations in North America. First documented in a New York cave in 2006, this disease is associated with more than seven million bat deaths. It spreads primarily from bat to bat and humans might be spreading the disease by carrying nearly invisible fungal spores on their shoes and clothing from one cave to another. Bat monitoring can help us understand changes occurring with the spread of this devastating disease.

Acoustic Monitoring

Forty-three acoustic recording stations were set up in 2015 and 2016 at Agate Fossil Beds National Monument to study bat summer habitat use. Acoustic recorders detect the unique ultrasonic calls bats use for echolocation. There were 67,917 bat call recordings from stations across all survey nights from 2015 to 2017. The data were analyzed through specialized software programs that make preliminary identifications of the bat species based on individual call characteristics, such as frequency and shape. Some bat species make calls that are similar to other species, which is why researchers with special expertise review the calls and make the final species determinations.

Bat acoustic monitoring equipment next to a rock outcropping
A bat acoustic monitoring station in Agate Fossil Beds National Monument.


Bats at the Park (2015-2017)

Nine bat species were detected at Agate Fossil Beds National Monument. Status is based on acoustic recording classifications in specialized software and researcher expertise.
Common Name Scientific Name 2015–2017 Status
Big brown bat Eptesicus fuscus Present
Eastern red bat Lasiurus borealis Present
Hoary bat Lasiurus cinereus Present
Silver-haired bat Lasionycteris noctivagans Present
Western small-footed myotis Myotis ciliolabrum Present
Little brown bat Myotis lucifugus Present
Long-legged myotis Myotis volans Present
Evening bat Nycticeius humeralis Probably Present
Tri-colored bat Perimyotis subflavus Present

  • Big brown, silver-haired, and hoary bats were were recorded more often than other species. The park wwas previously considered outside the range of big brown bats. Listen to a big brown bat call!
  • Hoary bat, long-legged myotis, evening bat, and tri-colored bat were new detections for the park.
  • Northern long-eared bats (Myotis septentrionalis) were previously reported as probably present, but could not be confirmed in this study. Since this species has suffered a dramatic decline in recent years, it may no longer be present or may be an infrequent park visitor. The northern long-eared bat (Myotis septentrionalis) is one of the species of bats most impacted by white-nose syndrome.
  • The highest rates of detection were at stations near trees and water where more roosting and foraging resources are found. In particular, the station in the cottonwood grove recorded a significantly higher than average number of bat calls. Without the cottonwood grove and the trees planted near the park buildings, there would likely be less bat activity at the Agate Fossil Beds National Monument.
gloved hands gently hold a fluffy chestnut coloreed bat, and stretch one of its wings out
The tri-colored bat (Perimyotis subflavus) is a new detection for Agate Fossil Beds National Monument. Here a biologist gently stretches the wing in order to take measurements.


White-nose Syndrome

White-nose syndrome has not yet been detected at the park, but the fungus (Pseudogymnoascus destructans) that causes it was detected in 2017 on bats at Badlands National Park, less than 100 miles northeast of Agate Fossil Beds National Monument. See a map of white-nose syndrome in national parks and learn more about how you can help prevent the spread of this fungus. Continued monitoring, and park staff and visitor observations, will help us protect the bat communities that live and forage in the park.

For More Information

Dan Licht, Midwest Region Wildlife Biologist
Protocol Contact: Northern Great Plains Network

Summary by Tani Hubbard, updated in 2019

Last updated: March 22, 2019