The disease causes a powdery white fungus to grow on the skin of hibernating bats, often on the face and wings, which causes irritation and dehydration. This causes bats to arouse early from hibernation and exhaust the fat reserves needed to survive the winter, often leading to their death.
Lick Creek Cave is one of a handful of caves in Montana that supports large numbers of hibernating bats during the winter, and biologists from Montana Fish, Wildlife & Parks and the U.S. Forest Service (USFS) conducted the survey there on May 18.
“We did not see the fungus associated with white-nose syndrome on the bats in Lick Creek Cave,” said Shannon Hilty, FWP nongame wildlife biologist. “But we did find the fungus inside the cave, and once we detect it, we typically find bats infected with the disease the following year.”
Hilty plans to survey the cave again in spring of 2024 to monitor for changes in the hibernating bat population.
WNS has been confirmed in 40 states and eight Canadian provinces, and FWP and partners have been monitoring bat populations in caves in Montana since the early 2000s. Systematic surveys began in Montana in 2011 and the fungus that causes WNS was first detected in the northeast corner of the state in 2020. The fungus has been detected in 16 Montana counties, and bats sick with WNS have been detected in four counties.
The disease can wipe out entire colonies of bats and has caused dramatic population declines in eastern North America. After WNS was detected in Azure Cave in the Little Rocky Mountains of Montana in 2020, a survey found a 98-percent reduction in bat numbers in the cave within two years. WNS does not directly affect humans, pets, livestock or other wildlife.
Bats are found throughout Montana and are an important component of the ecosystem and economy of the state, and also are part of the unique biological diversity of Montana. FWP has found the fungus that causes WNS in four of Montana’s 15 bat species.
“A little brown bat can eat 1,200 mosquitoes in an hour,” notes Kristina Smucker, nongame wildlife bureau chief for FWP. “Bats are tremendously important for keeping insect populations in check – they help protect crops and timber from flying insect pests, so we are very concerned about our bat populations and the impacts of this disease as we watch it spread across Montana.”
Bat populations are in decline nationwide. “We don’t yet have a good understanding of how bat populations will be affected by WNS in Montana,” says Smucker. “So, in addition to our disease surveillance efforts we are also placing acoustic detectors to record bat calls and monitoring bats at summer roost sites.”
Lick Creek Cave is located on the Helena-Lewis and Clark National Forest managed by USFS, and the agency is working with the state to mitigate the spread of the fungus.
“We are closing access to Lick Creek Cave in alignment with state guidance for controlling white-nose syndrome,” said District Ranger Helen Smith. “We will also be looking at closing neighboring caves to help mitigate the collapse of additional bat colonies.”
Questions on the cave closure can be directed to the Belt Creek-White Sulphur Springs Ranger district offices in Neihart, 406-236-5100, or White Sulphur Springs 406-547-3361.
What can the public do?
Cavers, climbers and recreationists that visit areas with roosting bats should remove dirt and mud from shoes, gear and clothing before leaving a site; bag these items to take home; and clean items promptly. People that visit multiple areas where bats might reside should follow decontamination protocols to help stop the spread of WNS: www.whitenosesyndrome.org/static-page/decontamination-information.
Anyone who sees a dead or sick bat, or group of bats, or finds bats in unexpected places, should not handle them, but rather call a local FWP office for further guidance.
“Like other wildlife, bats may get sick or die for a variety of reasons,” said Emily Almberg, wildlife disease ecologist for Montana FWP. “We are particularly interested in investigating clusters of dead bats or bats that are found dead during the winter or early spring, as that may indicate WNS being the cause.”
People can report these discoveries to the FWP Wildlife Health Lab in Bozeman at 406-577-7882, or they can contact a biologist at their nearest FWP office.
For more information on white-nose syndrome, visit www.whitenosesyndrome.org/. For more information on Montana’s bats visit fieldguide.mt.gov