Feared as sinister creatures of the night and reservoirs for viruses, bats get a bad rap.
But an emerging disease posing a severe threat to Colorado’s bats — unsung heroes of pest control that can eat thousands of insects a night — is highlighting the mammals’ importance to the state’s farmers and economy.
After two bats were found in Longmont and Boulder last month with white nose syndrome, a fungal disease that has decimated bat populations in the Midwestern and Eastern U.S., Colorado Parks and Wildlife has received at least a dozen more tips about dead or sick bats along the Front Range, said Bridget O’Rourke, an agency spokesperson.
Wildlife biologists collected the bats and are testing them to see if they were infected with white nose syndrome, O’Rourke said. Results are expected by mid-May.
It’s still unclear how quickly to expect a significant decline to the state’s bat population, but the impact could be devastating once the disease takes hold, said Brian Reichert, branch chief and coordinator for the North American Bat Monitoring Program, citing the severe decline in bat populations in more than two dozen states since the invasive fungus was detected for the first time in North America in 2006.
According to a 2021 study, co-authored by Reichert, three species of bats, including the Little brown bat found in Colorado, declined by more than 90% within seven years of being exposed to white nose syndrome. The Big brown bat, also found in Colorado, saw less severe but still serious declines, at 35%, researchers wrote.
At least 13 of the 18 bat species in Colorado are believed to be vulnerable to white nose syndrome, which was first discovered in the state in March 2023, according to CPW. The fast-moving disease is blamed for the death of 6.7 million bats across North America, according to nonprofit Center of Biological Diversity.
In Colorado, bats typically hibernate in small, isolated groups in places like talus in the mountains, under bridges, or in trees and buildings. That’s much different from bats in the Eastern U.S. that often hibernate in caves in colonies made up of hundreds of bats.
“So there is some thought that (Colorado bats) won’t spread the fungus that causes white nose syndrome as quickly,” Reichert said. “I’m cautiously optimistic, but we don’t have evidence one way or the other.”
One of his biggest concerns is the slow recovery rate if populations are decimated. Bats give birth to one to two pups per year, on average, he said.
“When their populations crash by 95, 96%, it takes a long time … for them to come back,” Reichert said.
The state developed a response plan to white nose syndrome aimed to prevent and minimize the human spread of the disease and where possible, help detect early signs of it.
See a bat?
CPW is asking the public to report any sightings of active or dead bats, or sites with hibernating bats, especially in eastern Colorado, to include in its monitoring. Call (303) 291-7771 or send an email to wildlife.batline@state.co.us. s here.
The public can help by being on the lookout for sick bats especially in the upcoming spring months, when bats should still be hibernating. White nose syndrome, named for the white fuzzy appearance on an infected bat’s nose, ears and wings, can cause the nocturnal mammals to leave hibernation sites early and fly during the day or dehydrate bats and prevent them from flying.
Bad news for Colorado’s farms
In a 2022 paper co-authored by a Colorado State University professor, data showed that white nose syndrome in bats, one of the largest groups of mammals (second to rodents), contributed an estimated $495 million to the U.S. agricultural economy.
As the bat population declined, researchers saw a ripple effect on food and agriculture. Farmers saw their yields plummet and were forced to spend more money on chemical pesticides for their crops to make up for pest control that bats previously provided.
“This is an example of how this natural population, sort of natural ecology, supports the economy that we depend on for jobs, food and income,” said Dale Manning, co-author of the study and associate professor of Agricultural and Natural Resource Economics at Colorado State University.
The largest impacts were to corn and soy production before land rental rates dropped, he said.
“As your costs go up and your yield yields go down, there are higher costs and lower revenues,” Manning said. “That willingness to pay for land is falling. So as a result, when the demand for something falls, its price falls and so that’s what we found in areas that lose these healthy bat populations.”
Another scientific study suggested that the loss of bats in North America could lead to agricultural losses estimated at more than $3.7 billion a year.
While Colorado’s ecosystem is different and its climate is much drier than in the East, Manning said he expects Colorado to see a loss of the pest control as the disease spreads.
Bats are voracious insect eaters and play a large role in ridding the environment of tons of noxious and agriculturally damaging moths, mosquitoes and other pests. The Little brown bat can catch and eat more than 150 mosquitoes and other pests in less than 15 minutes, according to CPW.
“Corn producers are probably the most susceptible based on what we found in the rest of the country,” Manning said.
Colorado’s 18 species of bats live in every corner of the state from the Eastern Plains to the high-elevation mountain forests, to Western deserts and downtown Denver. Experts fear the impact the loss of bats could have on the state’s forests, where the nocturnal mammals also play a vital role in regulating insect populations.
What you can do to help Colorado’s bats
Wildlife biologists are closely monitoring bats around the state, including a colony off the Poudre River where the fungus that causes white nose syndrome was detected, Reichert said.
But it is much trickier to keep tabs on the cryptic creatures because of their isolated hibernating sites. This year, biologists will try to get to known bat sites earlier to increase chances of observing any signs of the disease as bats emerge from hibernation, he said.
Community scientists through the Colorado Bat Watch monitor often hard-to-find roosting sites, or places where bats live, to help biologists monitor the state’s population.
“It’s like a needle in a haystack. Just think about looking in all of the trees in Colorado to find where bats are roosting in trees,” said Megan Mueller, a conservation biologist with Rocky Mountain Wild, which runs the program.
The public can also conduct sunrise or sunset surveys to look for flying bats emerging from a roost and report any bat sightings.
Locating roosting sites is key as scientists race to create a vaccine that could protect bats against the virus, Mueller said.
“It may eventually be possible to apply those vaccines at roost sites, only if we know where they are,” she said.
It’s also important to track bats to protect them from other threats, like building development, wind energy and habitat loss.
The fungus that causes white nose syndrome does not infect humans or pets, and bats are the primary way the fungus spreads. But the fungus can be transported on gear and clothing, so people who visit caves should decontaminate their gear to prevent spreading it.
The U.S. Forest Service has implemented restrictions on cave access in the Rocky Mountain region and requires cavers to follow decontamination procedures and apply for permits to help limit the spread of the fungus.
The agency implemented an emergency order in 2012, shutting down complete access to hundreds of caves and roughly 30,000 abandoned mines on National Forests in the region. In other states, like Arkansas, caves were shut down for several years to protect bats.
“Given that white nose is going to likely kill a lot of bats in Colorado, we need to be doing a really good job of protecting bats from other threats,” Mueller said, “so that they have a chance to survive white nose and and don’t have to be stressed by other threats at the same time.”