Bat Acoustic Monitoring at Fort Laramie National Historic Site

A redish brown bat hangs upside down while two grey baby bats cling to her fur
Eastern red bats (Lasiurus borealis) were a newly detected species at Fort Laramie National Historic Site. This picture of a mother with three babies was not taken at the park.

© Josh Henderson (


Fort Laramie National Historic Site is an 833-acre park that conserves and interprets historic Fort Laramie in southeastern Wyoming. The North Platte and Laramie rivers converge in the park, and the riparian forest along these rivers provides good roosting and foraging habitat for bats. The Fort grounds also attract bat species that roost in structures. To try and keep bats out of the historic buildings in the park, a special bat house was built within the grounds but away from the historic district.

The Northern Great Plains Inventory & Monitoring Network monitors bats to detect long-term trends in bat populations at the park. Six acoustic recording stations were set up at Fort Laramie National Historic Site for long-term monitoring: three in riparian forests, one at the bat house, one on the Fort grounds, and one along a canal that borders the park. Acoustic recorders detect the unique ultrasonic calls bats use for echolocation. There were 205,769 bat call recordings from stations across all survey nights from 2015–2017. 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 on a tripod on a grassy bank of a river
A bat monitoring station in the riparian area at Fort Laramie National Historic Site.


Highlights (2015- 2017)

  • Nine species were confirmed present or probably present in the park: big brown bat (Eptesicus fuscus), eastern red bat (Lasiurus borealis), hoary bat (Lasiurus cinereus), silver-haired bat (Lasionycteris noctivagans), western small-footed myotis (Myotis ciliolabrum), little brown bat (Myotis lucifugus), long-legged myotis (Myotis volans), Yuma myotis (Myotis yumanensis), and tri-colored bat (Perimyotis subflavus).
  • Little brown and big brown bats were recorded more often than other species. These bats were highly active in both the riparian forests and around the historic structures and bat house. The bat house is proving very effective at supporting a population of little brown bats, and it is likely that they are a maternity colony.
  • Eastern red bat, long-legged myotis, and tri-colored bat were new detections for the park. Listen to an eastern red bat call!
  • Bats were most active just before dawn on the Fort grounds. They likely swarm near the historic buildings prior to roosting for the day and depart the buildings quickly at night in search of food and water.
  • The riparian forests had the most bat species and consistent activity since bats are likely using this habitat for foraging and roosting. The canal site has most activity just after sunset indicating that this area is likely used for drinking and foraging only.
  • Fort Laramie National Historic Site had the highest rate of bat activity of any park in the Northern Great Plains Network.
A wooden house-shaped structure on stilts
The bat house at Fort Laramie National Historic Site was created to help keep bats out of the historic structures. It is popular with little brown bats (Myotis lucifugus).


White-nose Syndrome

White-nose syndrome is a rapidly expanding fungal disease that 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.

While white-nose syndrome has not yet been detected here, the fungus (Pseudogymnoascus destructans) that causes it was detected in May 2018 on a little brown bat at the park. 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 2018

Last updated: August 15, 2018