Knife River Indian Villages National Historic Site is a 1,749-acre park just north of Stanton in central North Dakota that protects and interprets the remains of historic Hidatsa villages. The upland woodlands and cottonwood forests along the Knife and Missouri rivers provide foraging and roosting habitat for bats. Some bats can eat thousands of mosquitoes each night, making them important for insect control in the croplands that surround this park.
The Northern Great Plains Inventory & Monitoring Network monitors bats to detect long-term trends in bat populations and activity at the park. Four acoustic recording stations were established in 2015 at Knife River Indian Villages National Historic Site: one near the visitor center, two along the Knife River, and one in the woodlands area. Acoustic recorders detect the unique ultrasonic calls bats use for echolocation. There were 18,058 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.