Nate Schwab knows the sound that bats make when the creatures are eating or flying or chasing prey.
"If you divide the frequency, it just sounds like clicks," said Schwab, who has worked with bats in 15 states.
Last week, the senior bat ecologist at TetraTech was orienting a team of four workers to deploy bat monitoring equipment for a project the University of Montana's Center for Integrated Research on the Environment launches at the end of this month.
It's part of a five-year, $45 million agreement between the U.S. Army Corps of Engineers and UM to "study and solve environmental and cultural resource problems across the nation."
In a partnership with the Department of Defense and the Corps of Engineers, the center is sending teams to set up bat monitoring stations on 14 different U.S. Air Force Bases in the Midwest with the goal of surveying for the presence of the Northern Long-eared Bat.
"CIRE's involvement is particularly exciting as the DOD seeks to bridge the gap between academia and applied field research," said the center's Austin Blank in a statement.
The Northern Long-eared Bat became a protected species in April 2015, and the Air Force called for the survey in order to ensure it's following Endangered Species Act requirements, according to a news release from UM.
This summer the team, including three military veterans, will travel to the bases to install the equipment, 70 monitors in all. Last week on campus and in Greenough Park, they learned to identify the best places to set mics to capture the echolocation of bats, and they also went over the setup routine.
"We're trying to be as efficient as we possibly can so we're trying to get in some practice," Schwab said.
On Wednesday, Schwab led C.T. Callaway, Jake Howard, Tina Cain and Ingrid De Groot down a trail in the park as one member of the group pulled a wagon filled with components of the outdoor microphone stand. On the bank of the Rattlesnake Creek, Schwab circled the workers for a look around.
"Optimally, we're looking at about 30 meters of vegetation-free space," he said.
Western Montana is home to 11 or 12 species of bats, and Schwab pointed out the places near the creek that bats might find appealing. They'd roost under bridges and behind bark, so placing the mic near the old snag with many cracks would be a good idea.
On the south end of the park, the canopy wasn't open enough, but the lesson stood: "If you see a lot of snags around, might be a good idea to place it here," Schwab said.
The group moved on, and in a place where the trees opened to a clear view of the stream and the canopy, Schwab saw potential, and so did Callaway.
"There's a lot of bugs flying around here, so could be a lot of bats feeding," Callaway said.
Schwab agreed, and he liked the way the group could orient the mic so it could catch the sounds the bats made as they flew along the tree line. The human ear doesn't register the high frequency sound from bats without assistance.
Once the group got to work, it took less than six minutes to pound the tripod into the ground, set the mic on the pole 10 feet off the ground, hook up the battery and bat recorder, and stake the station.
Since 2006, the population of the Northern Long-eared Bat has dropped 90 percent in North America, all due to white-nosed syndrome, Schwab said. At the same time, he's feeling hopeful about the species.
"Just recently, I feel like there's been a raised consciousness about bats from the public, for whatever reason," he said.
When the crew finished, they plugged ear buds into the system for a listen, and Schwab asked if they heard any interference: "Did you hear any other high frequency noise?"
They didn't, and the scientist was pleased; the mic sat close to the creek, and sometimes, water interferes.
On the bases, the group will work in teams of two, and at the end of the summer, they'll have a list of bat species for each location. For the workers, the draw for the project is the travel and the learning.
"It's also interesting to get a fresh perspective on something I never really knew about," Callaway said.