Living with Wildlife
Living with Bats
There are roughly 20 bat species that live in Colorado; some are here year-round and some only migrate through the state. Though commonly misunderstood, bats actually play a valuable role in ecosystems across Colorado.
Bats can be found in every habitat in the state, from the eastern plains to the high mountain forests and western deserts, from rural towns to downtown Denver. All of our bats eat insects and help control our insect populations. The Little brown bat has been known to catch and eat more than 150 mosquitoes and crop pests in less than 15 minutes!
Colorado Parks and Wildlife continually monitors bat populations as part of a nationwide effort to detect changes from challenges including white-nose syndrome, climate change, energy and land use development.
Do You Have Bats In Your Building?
If you are having trouble with bats using a building, they can be excluded humanely by sealing access points. Timing is important to avoid killing bats and their pups, as trapping them will create more headaches for you with bats ending up in living spaces as they try to escape. Avoid sealing bats out of buildings during pupping season from June-August.
During migration time, finding a bat hanging under the eve of a house, under a porch over-hang, hidden behind shutters or gutters or in a tree is normal. Just leave bats alone and usually they will leave on their own.
What to Do if I Find a Bat?
Please do not handle the bat but place a box or can over them to prevent disturbance.
Report a Bat Sighting
To help with White Nose Syndrome surveillance, CPW is asking the public to report sightings of any active or dead bats between the months of December through June, as these bats might be sick from WNS. A special phone line 303-291-7771 and an email address are available to report these sightings. Report sightings via email to: [email protected]
Other Bat Encounters
For all other bats encountered from July through November OR any time you have had contact with a bat without protective equipment like leather gloves, please contact your local County Health Department immediately. Please see “Do You Have Bats In Your Building” for all questions related to bat roosts.
Find your local County Health DepartmentSick Bats
White-nose syndrome is a serious threat to bats, and this film seeks to inform about this disease to help stop its spread
What Is White-Nose Syndrome?
White-nose syndrome (WNS) is the name of a disease caused by a fungus (known as ‘Pd’) that results in a white, fuzzy fungus that grows on the face, ears, and wing tissue of infected bats. The fungus that causes WNS thrives in cold temperatures from 5 to 15 deg C (14 to 59 deg F) – the same temperature range found in bat hibernacula. Hibernating bats reside in an inactive state during the winter months, during which time their immune system is suppressed, making them vulnerable to infection. Consequently, the fungus does not affect non-hibernating bats.
Infected bats may arouse from hibernation due to the damage caused by the fungus. Bats that frequently arouse tend to prematurely use their fat stores saved for winter, resulting in starvation. WNS first appeared in the United States in 2006 and has resulted in population-level mortalities of bats across the country.
What to Look For
- Grounded bats that are dead or acting lethargic during the winter and early spring months (December – June statewide; December – July in high elevation areas).
- Bats with highly damaged wing tissue.
White Nose Syndrome in Colorado
The fungus was confirmed in Colorado during the summer of 2022 and the first bat to die of the disease, a Yuma myotis, was found at Bent’s Old Fort National Historic Site in the spring of 2023. Since that time, the fungus and disease has been confirmed in additional counties and species. CPW continues to monitor the spread of the disease in Colorado and is conducting vaccination trials to see if proactive measures can be used to protect bats.
Bats are an essential and beneficial part of the ecosystem. Please see whitenosesyndrome.org for more information.
Positive Tests
White Nose positive Counties:
- Boulder
- Douglas
- El Paso
- Grand
- Jefferson
- Larimer
- Otero
- Routt
- Teller
- Weld
White Nose positive species:
- big brown bat
- fringed myotis
- little brown myotis
- Long-legged myotis
- Western long-eared myotis
- Western small-footed bat
- Yuma myotis
Fungus (Pseudogymnoascus destructans) only positive Counties:
- Baca
- Jackson
- Montezuma
- Pueblo
- Routt
Fungus (Pseudogymnoascus destructans) only positive species:
- Mexican free-tailed bat
- Townsend’s big-eared bat
Help Protect Bats
Humans may transmit WNS from infected sites such as caves to clean sites. This kind of spread is most likely occurring from boots, clothing and equipment that are not properly cleaned and decontaminated between sites. Because of the devastating effects of WNS, it is critical that people make sure we are not spreading WNS.
- Please do not use ANY gear or clothing in the west that you have used in caves/bat roosts in areas where WNS has been confirmed. There is a risk that you could spread the fungus that can kill bats.
- Please ensure ALL gear and clothing used in western caves and roosts has been cleaned and disinfected before entering any other caves/roosts in the west. Soaking equipment for at least 20 minutes in water kept at 120 degrees, or using approved disinfectants such as Lysol all-purpose professional cleaner as recommended.
Please see the official decontamination guidance and protocols for researchers and cavers on the white-nose syndrome.org website.
Signs of a Rabid Bat
Bats are an important part of the ecosystem because they eat mosquitoes and other insects and pollinate plants. Bats should not be killed indiscriminately or because of a fear of rabies.
Like many wild animals, bats can carry rabies. The vast majority of bats are healthy, do not have rabies, and pose no risk to people." Studies have suggested that less than 1 percent of all bats may be infected. Due to successful dog and cat vaccination programs, rabies is now the second rarest disease in the United States and Canada, behind polio.
Rabies is a fatal disease caused by a virus that can affect any mammal species. In Colorado, the most common species that transmit rabies are bats and skunks, though other mammals such as raccoons, foxes, etc. may also transmit the virus. Exposures are rare in Colorado, but they do occur. Colorado Department of Public Health and Environment maintains data for public knowledge, including a list of rabies detections by county and species.
- Infected bats may appear healthy due to the prolonged incubation period of rabies
- Infected bats can show variable clinical signs ranging from lethargy to aggression; any bat that is acting abnormally should be treated as a suspect
- Daytime activity does NOT always indicate that a bat has rabies; however, any abnormal behavior (including daytime activity) can be a sign of illness
Crossing Paths with a Sick or Injured Bat
Sick or injured bats should be safely confined and reported to your local CPW office.
Avoid contacting sick or injured bats, when possible. The most common occurrences of human exposure to bat bites/scratches include picking one off the ground, trying to remove a bat from the house, taking a bat from a family pet, and having a bat land on them. Bats found in a room with children, sleeping people, and/or nonverbal adults may also pose a risk. Exposure to bat bites and scratches may not be obvious and any interaction with bats should be reported to your local public health official.
- Always wear heavy gloves if you need to move or confine the animals.
- Bats on the ground or other surface may be confined by placing a container, such as a coffee can or food container, on top of the animal. Slide a piece of cardboard or heavy paper between the container and the surface and tape it shut.
- Keep away from children and pets.
What to do if You or Your Pet is Bitten or Scratched?
Bat teeth are small and very sharp, so a bite wound may be no more than a pin-like puncture, or it may not be visible at all. All bat encounters should be treated as possible exposures and should be reported to your public health official immediately.
- If you were bitten or scratched by a bat, clean the area with a significant amount of soap and water, then apply alcohol or iodine. Contact your local public health official and physician immediately.
- If your pet was bitten by a bat, had a bat in its mouth or was near a grounded bat, contact your veterinarian.
Protecting Pets
Keeping domestic dogs and cats vaccinated against rabies is the best practice for disease prevention. Pets with access to the outdoors are more likely to come in contact with bats and other wildlife, increasing their risk of exposure and chance of bringing unwanted wildlife into the home. Any possible or confirmed pet exposure to bat should be reported to your veterinarian immediately.
For resources on protecting horses and livestock against rabies, talk to your veterinarian and visit the Colorado Department of Agriculture website.
Get Involved
Community scientists can get involved with bat conservation in a collaborative effort with Colorado Bat Watch
Find out moreBats of Colorado
Tri-Colored Bat
The tri-colored bat has tri-colored dorsal hairs, thus it gets its common name of tri-colored bat.
Brazilian Free-Tailed Bat
This bat is well known for its large colony that summers in the San Luis Valley.
Silver-haired Bat
A slow-flying bat that is often seen near woodland ponds and streams, they are sometimes hooked by anglers fly-fishing.
Canyon Bat
This tiny bat has a stuttering flight and can often be found in arid canyons near waterways.
Pallid Bat
A pale-colored bat with large ears, it can often be found living in human-made structures, which allow it to extend beyond its natural range.
Hoary Bat
This bat is distinctive, with fur that appears tipped in hoar frost.
Red Bat
As the name indicates, this is a colorful bat, varying from bright reddish to orange.
Big Free-Tailed Bat
Big free-tailed bats are found in deserts and arid grasslands, where they roost in rocky outcrops and cliffs.
Townsend's Big-Eared Bat
This bat has remarkable ears that can reach an inch and a half in length.
Big Brown Bat
Perhaps not the most creatively-named, this is the most common, and therefore one of the most important, bats in Colorado.
Spotted Bat
With huge pink ears and white spots on its back, this is Colorado's rarest bat.