Colorado steps up bat monitoring during hibernation season

Townsend's big-eared bats are a species of concern in Colorado and could be susceptible to white-nose syndrome, which is wiping out bat populations in the Northeast. PHOTO COURTESY DIVISION OF WILDLIFE.

Biologists trying to keep deadly white-nose syndrome out of state

By Bob Berwyn

SUMMIT COUNTY — Colorado Division of Wildlife biologists are closely monitoring bat caves in the state to look for signs of white-nose syndrome, caused by a fungal parasite that has devastated bat populations in other parts of the country.

The agency has developed a response plan, which will soon be posted at this CDOW website, but the main goal is to try and prevent the fungus from spreading into the state, according to Tina Jackson, a species conservation coordinator with the division of wildlife.

The best way to do that is to keep people out of caves and the Forest Service has closed caves on national forests lands in Colorado and surrounding states. Biologists are asking Colorado residents and visitors to respect those closures, and also to report signs of white-nose syndrome, including:

•    Bats moving to the openings of the hibernation site during the winter
•    Bats leaving hibernation sites in the winter, especially on cold days
•    Bats with a white powder-like material on their nose, ears or wings
•    Dead bats

The Division of Wildlife would also like to know of any sites, especially in eastern Colorado, that have hibernating bats so biologists can include them in the monitoring effort. General info on Colorado bats is online at this CDOW website.

There is no effective way to treat bats once they’ve been attacked by the fungus, which has spread rapidly in the eastern U.S. Most recently, Indiana and North Carolina officials reported finding white-nose syndrome in bats in their states.

“Bats are an important yet under-appreciated part of our world and this threat is something we should all be worried about,” said Tina Jackson, a Species Conservation Coordinator for the Division of Wildlife. They play a huge role in controlling insect populations and in pollinating many species of plants. Losing significant numbers of bats would create huge problems for agriculture, she explained.

The flying mammals are most susceptible to the fungus during their winter hibernation, when their immune system shuts down, Jackson explained.

White-nose syndrome, which is caused by a fungus known as Geomyces destructans, is responsible for large-scale bat die-offs in the Eastern United States. In the four years since it was first discovered, white-nose syndrome is responsible for the death of more than one million bats.

White-nose syndrome is named for the white, powder-like material seen on the nose, ears, and wings of infected bats. It probably was spread from from Europe to the U.S. by cave explorers.

Some bats in Europe may have developed immunities that bats in North America don’t possess. Without any natural protections, white-nose syndrome can wipe out 95 percent of a bat colony in a couple of years. As a result, white-nose syndrome could eliminate little brown bats in the northeastern U.S. within 16 years.

White-nose syndrome has not been found in Colorado. Since being first documented in 2007 in a cave in New York, white-nose syndrome has spread to 16 states and 2 Canadian provinces. In 2010, a cave in northwestern Oklahoma and less than 200 miles from the Colorado border tested positive for the fungus.

Scientists speculate that the fungus jumped from Europe to the US through human transmission. They also believe that a large jump from the East Coast to a cave in Oklahoma was probably someone who had explored an infected cave and then traveled west with the fungus on clothing or equipment.

“Once the fungus arrives in an area, it can spread quickly as bats move,” said Jackson. “But the fungus makes the biggest leaps in distance when it moves because of human activity.”

Jackson said there’s not a lot of information on bat migration, so it’s not clear whether the fungus could spread from Oklahoma to Colorado without human help. There are places where populations of bat species overlap, and future research projects could help determine how much those populations mingle.

Bats in colonies infected with white-nose syndrome seem to arouse from hibernation more frequently than uninfected populations, possibly because of irritation, hunger or thirst. The increased number of arousals from hibernation quickly depletes the bat’s fat reserves and results in starvation. The fungus also causes damage to the wings affecting the health of the bat and perhaps compromising the ability to fly and capture insects.

Colorado is home to at least 18 species of bats, 13 of which are believed to hibernate in the state. Bats that migrate to warmer climates for the winter are not believed to be effected by white-nose syndrome.

All the bat species found in Colorado are insect eaters, in some cases eating thousands of insects a night. This diet of night flying insects makes bats important for the control of agricultural and human pests. Bats are also important to the cave environments they roost in, bringing energy into these mostly closed systems in the form of their guano.

Members of the public who see any active or dead bats this winter are asked to report that information to a special phone line (303-291-7771) or e-mail address ( Because bats also can be affected by other health problems, including rabies, people should use precautions such as disposable gloves or an inverted plastic bag when handling bat carcasses. The public is also advised not handle live bats that appear to be ill.

For more information on white-nose syndrome, visit the DOW web site at:

A photo of Colorado’s largest bat colony at the Orient Mine is available at:

For more news about Division of Wildlife go to:


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