A fungus that has killed millions of bats in the eastern and central parts of the U.S. is now spreading across the West. Biologists recently detected it for the first time in Montana. Local scientists are collecting data inside caves, below bridges and under the night sky.
"Keep two hands on, and you should be good."
At the Azure Cave in north-central Montana, climbing expert Zach Angsted helps several people rope up. One of them is Lauri Hanauska-Brown, the nongame wildlife management bureau chief for Montana Fish, Wildlife and Parks.
"OK, so we’re just getting started," Hanauska-Brown says. "We’re about to go over the first cliff. How long is this first descent, Zach?"
"Seventy feet," Angsted says.
"Seventy feet, and so far we’ve got five bats that are quietly hanging on the walls.”
The goal today is to swab live bats and collect samples of feces, or guano.
"So you don’t rub it like this," Hanauska-Brown says while demonstrating. "You want to roll it across the wing and across the nose, several times, both. Take this Q-tip; dip it back in here."
Their work is part of a large-scale effort to track something that’s causing massive numbers of bats to die in North America, something that just showed up in Montana.
FWP announced last week that samples of bat guano under bridges in Daniels, Richland and Fallon counties tested positive for a fungus called Pseudogymnoascus destructans, which scientists often refer to as PD.
"It’s like a mold that’s growing on their bodies," Hanauska-Brown says.
The white fungus can spread between bats when they squeeze through the same small cracks in caves or roost in tight clusters during their winter hibernations.
"We believe that it’s so irritating that they wake up. Sometimes it appears to be dehydrating them. There’s all sorts of different things going on physiologically."
Hanauska-Brown says this can disrupt their metabolisms and deplete the fat reserves they need to make it through winter.
White-nose syndrome, the disease caused by the PD fungus, was first discovered in New York state in 2006. Since then, it has spread to several dozen states and Canadian provinces, wiping out 6.7 million bats in North America.
Kimberly Dickerson with the U.S. Fish and Wildlife Service is the White-Nose Syndrome Coordinator for eight states stretching from Montana to Kansas.
"It was found in Nebraska and Kansas early on, and two years ago, then it was found in South Dakota and in Wyoming," Dickerson says.
In May, the North Dakota Game and Fish Department reported white-nose syndrome killed a cluster of little brown bats, not far from Montana’s border. FWP announced the fungus had been detected in Montana on June 15th.
Lauri Hanauska-Brown with FWP says the PD fungus is not known to affect humans, pets, livestock or other wildlife, but people should be concerned about large-scale die-offs of bats.
Bats act like natural pesticides, eating the insects that damage crops and trees.
"If you just don’t like mosquitoes, you’ve got to thank the bats because without the bats around, we would likely have more mosquitoes, which can lead to more disease transmission, etc., etc. so their role in that cycle of ecosystem health is really important," Hanauska-Brown says.
To understand where and how the fungus is spreading, she says getting good data is key.
In addition to collecting samples from bats, FWP is partnering with the Montana Natural Heritage Program to find out where bats live in the state via acoustic monitoring. During June and July, crews set up devices across Montana that record the echolocation calls bats make when they’re active at night.
The heritage program’s senior zoologist Dan Bachen says this will boost the state’s baseline data, allowing scientists to recognize sudden declines in a bat population and long-term trends.
"We need ways to continue to monitor to see if diseases like white-nose syndrome actually are having the same impacts that they do in other areas of the country, and if any treatment is developed, we can deploy that effectively," Bachen says.
Currently, no cure exists for white-nose syndrome, but scientists around the world are working on several experimental treatments, including a vaccine.
Bachen says the extent to which the fungus will affect the 15 species of bats in Montana is also uncertain.
Scientists know some species, like the little brown bat, which lives throughout much of North America, are very susceptible. But there isn’t a lot of evidence showing what the PD fungus means for other bat species that only live in the West.
Secondly, just a small percentage of bats in Montana use caves compared to their counterparts in the East. Emily Almberg, a disease ecologist with FWP says this could help slow the spread of the fungus.
"The conditions of caves, in terms of humidity and temperature, are what drive, in large part, the maintenance of the fungus," Almberg says, adding a lot of bats in Montana use rock talus slopes and tree roosts.
They’re more spread out compared to some of the bat populations on the east coast.
"There is this fair open question about how it will play out in the West. You know, we’re hopeful that it will look different. I don’t know that it will, but we’re hopeful," Almberg says.
She says cavers and climbers can help prevent the spread of the fungus by following decontamination protocols, which can be found on the White-Nose Syndrome Response Team’s website, along with other resources.
North American bats do notcarry the type of coronavirus that causes COVID-19. But there is concern that humans could accidentally transfer it to the bats. FWP has temporarily prohibited the live handling of these animals.
Anyone who sees a sick or recently deceased bat or group of bats should contact health officials or state biologists who can provide further guidance.
Wildlife photographer and filmmaker Ronan Donovan provided YPR with audio from Azure Cave while researchers collected samples.