Chollas cacti dominate the landscape on the sprawling Walker Ranch just north of Pueblo. In early June, grasshoppers chirp, and swooping birds trill.

Those are not the sounds Ed Schmal is searching for with audio detectors zip-tied to tall poles along fence lines and transmission towers. Schmal is looking for evidence of an entirely different soundscape, one mostly undetectable to the human ear.

The Colorado Parks and Wildlife conservation biologist is interested in the sonic signatures of Colorado bats. Mostly ultrasonic, each bat species produces a unique sound wave that can be picked up by Schmal’s monitoring equipment. A bat’s signature looks a bit like the Nike “swoop.”

“Everything else is going to look very differently on the sonogram,” he said.

CPW has had the unobtrusive microphones and equipment on the ranch for a decade, collecting data for a nationwide project to better understand the often elusive creatures. Colorado has 20 species of bats, carving out niches in the state’s varied environment. Instead of the stereotypical caves, they mostly roost in small numbers wherever cover can be found; in trees and among talus rock slopes, in attics and the undersides of bridges.

Schmal has documented nine different species on a few acres of the Walker Ranch over the years. He is hoping, in the wake of a catastrophic bat disease making its way into the state, those nine continue to appear in the data.

“I think it’s spreading everywhere,” he said.

The first case of white-nose syndrome in Colorado was discovered in spring of 2023 at Bent’s Old Fort National Historic Site, about 70 miles to the west of Schmal’s research site. The deadly fungus that causes the syndrome has been attributed to millions of bat deaths since its discovery in 2006 in New York, with a near-total fatality rate for many infected colonies.

A victim might have papery, lesion-filled wings, said Schmal.

The fungus doesn’t always kill bats outright. Rather, by forcing infected animals to come out of hibernation to groom or leave their compromised roost, it puts bats in a weakened state to withstand winter.

“Not only is the tissue being damaged, but the animal is basically starving to death,” explained Dan Neubaum, CPW species conservation program manager.

The jump into Colorado did not come as a surprise. The disease has been spreading around the state like a boulder breaking the surf on a beach, said Neubaum. It was only a matter of time.

Since 2023, cases have been detected elsewhere in the state. First among the bats of the plains, documented cases are climbing in elevation.

Not every species of bat is affected the same by white-nose syndrome, and Neubaum said researchers are hoping that the difference in habitat and behaviors between Eastern U.S. and bats in the West might prevent a similar devastation. A drier climate might not promote the fungus as well, while dispersed bat populations could slow spread.

“If the infection is lower and slower, we might see that from the very start,” he said.

The problem with documenting those differences is that much is still unknown about Colorado’s bats, especially those on the Eastern Plains.

“We don’t even know where most of our bats are,” Neubaum said.

Colorado bats can be anywhere, and those roosting choices are not obvious without following radiotransmitter-attached individuals back to their homes. If a population is badly affected with white-nose syndrome, the evidence might not be easy to find.

Schmal’s efforts on the Walker Ranch are one part of the effort to better understand the baseline of the state’s bat population before it is rocked by white-nose syndrome. In addition to ultrasonic monitoring, he’s also been out trapping specimens this year. Pueblo County, where Schmal is based, has seen multiple cases of the disease this spring.

The national database that will eventually catalog Schmal’s sonic data is the North American Bat Monitoring Program (NABat) and is primarily run by the U.S. Geological Survey.

Schmal is concerned that NABat, like other federal environmental programs this year, might lose key staff or disappear altogether under the weight of funding cuts. He said the longitudinal data NABat logs is rare for a non-game species.

“We could lose this entire program,” he said.

According to an internal email obtained by the journal Science, the Trump administration is expected to ask Congress to cut all biological research at USGS, a branch of the Department of the Interior, in the 2026 budget.

If Colorado bats begin to disappear, the vacancy might have far-reaching effects. Bats occupy a space in the food chain, so white-nose syndrome could harm the equilibrium of predator species like owls.

Bats also provide “ecological services” to humans, says Schmal. Namely, bats are major predators for insects. With fewer bats, the insects that destroy crops and otherwise bother humans increase.

“Change to the insect community could be one of the big things that we see, and we don’t fully understand what that’s going to look like, either,” said Neubaum.

USGS researchers have developed a vaccine for the disease that is currently going through field trials, including one in Colorado. At one testing site near Steamboat Springs, Neubaum said the established colony with a documented infection is under study.

“It’s going to be interesting to see how those individuals fare and whether it helps or not,” he said.

Scaled administration is still a barrier.

“We know realistically that we can’t reach a huge portion of the population to apply that method,” he said.

Schmal’s detectors will run for about a week collecting sound signatures — indirect evidence of what one of the state’s most mysterious creatures is up to from dusk until dawn every night.

Neubaum said the enigma is part of bats’ charm.

“I think I like them because there are so many unanswered questions for them,” said Neubaum.