Bat Acoustic Monitoring at Fort Laramie National Historic Site

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 (https://creativecommons.org/licenses/by-sa/2.0/legalcode)

Overview

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 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 helps us understand changes occurring with the spread of this devastating disease.

Acoustic Monitoring

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 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.

A bat monitoring station in the riparian area at Fort Laramie National Historic Site.

NPS

Bats in the Park (2015- 2017)

Nine bat species were detected at Fort Laramie National Historic Site. 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	Probably Present
Little brown bat	Myotis lucifugus	Present
Long-legged myotis	Myotis volans	Present
Yuma myotis	Myotis yumanensis	Probably Present
Tri-colored bat	Perimyotis subflavus	Probably Present

• 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. Historic structures are being used for roosting, but 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!
• The Yuma myotis was detected in multiple years, although the park is generally reported to be just east of that species' range.
• 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.

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).

NPS

White-nose Syndrome

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 2019