Bat Acoustic Monitoring at Mount Rushmore National Memorial

Tri-colored bat held by a researcher gently spreading its wing for measurement
The tri-colored bat (Perimyotis subflavus) is a new detection for Mount Rushmore National Memorial.

NPS

Mount Rushmore National Memorial is a 1,278-acre park in the center of the Black Hills in South Dakota established to protect the faces of four presidents carved on the mountainside. Granite outcroppings and the old growth ponderosa pine forest that surrounds the mountain may provide good bat roosting habitat.

The Northern Great Plains Inventory & Monitoring Network monitors bats to detect long-term trends in bat populations at the park. Ten acoustic recording stations were established in 2015 at Mount Rushmore National Memorial. Acoustic recorders detect the unique ultrasonic calls bats use for echolocation. There were 44,796 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.

Researcher setting up an acoustic recording station by a marsh
An acoustic recording station near the old beaver pond that is now a marsh at Mount Rushmore National Memorial.

NPS

Highlights (2015–2017)

  • Eleven species were confirmed present or probably present in the park: Townsend's big-eared bat (Corynorhinus townsendii), 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), northern long-eared bat (Myotis septemtrionalis), fringed myotis (Myotis thysanodes), long-legged myotis (Myotis volans), and tri-colored bat (Perimyotis subflavus).
  • Silver-haired and hoary bats were most commonly recorded, followed by big brown, eastern red, and little brown bats. Hear a silver-haired bat call!
  • A very small number of the acoustic recordings were attributed to the northern long-eared bat.
  • The hoary bat, an open country flyer, was recorded most often in the open area around the visitor parking garages. The smaller and more maneuverable little brown bat was detected more often in forests.
  • The station with the most bat recordings was at the old beaver pond in Starling Basin, a diverse site surrounded by forest with dead snags for roosting and a marsh where the beaver pond used to be that is likely good for foraging. The clearing between the visitor parking garages had the next highest rate of bat activity, perhaps because bats forage on the insects attracted to the lights and warm surfaces.
  • Preservation of the old growth ponderosa pine forest, including dead snags, will protect the bat community. Silver-haired bats, long-legged myotis, and northern long-eared bats are particularly reliant on high densities of snags.
Little brown bat with white fungus on its nose
Little brown bats (Myotis lucifugus) have been particularly hard hit by white-nose syndrome, but we have not yet detected the disease on any bats at Mount Rushmore National Memorial. Continued monitoring will help protect the park's bat populations.

USFWS/Marvin Moriarty

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.

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 nearby Badlands National 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 created by Tani Hubbard, updated in 2018

Last updated: August 15, 2018