Learn How to Spot Roosting Bats and Report Your Observations
Do a sunset or sunrise survey.
You don’t need any experience and you may not even need to leave your backyard!
Anytime between May and September, simply spend the hour after sunset or the hour before sunrise watching for bats. You can do this in your yard, or at a local park or open space. You can find bats in the middle of urban areas, in small towns, on farms and ranches, and out in nature (in prairies, deserts, canyons, forests and mountains).
Look for bats flying.
You can do this anywhere, and you may be surprised by where you see bats once you start looking. Areas near ponds, lakes or rivers can be good places to look.
If a bat is not flying, then it is roosting.
If you see bats flying, it might mean a roost is nearby. Bat roost sites are where bats live. Roost sites provide shelter and protection from predators when bats are not active, and a safe place for female bats to give birth and rear young. Bats roost in attics, barns, outbuildings, bat houses, bridges, culverts and other human structures, trees, talus (piles of rocks in the mountains), caves and mines. We are especially interested in observations of bats roosting in human structures, trees and talus.
Look for bats emerging from a roost at dusk.
If you think a human structure, tree or area of talus might have bats roosting, then take a look from a distance at sunset to see if you can spot bats emerging or flying around hunting for insects. Look for bats emerging from:
- attics, barns, outbuildings, bat houses, bridges, and culverts
- tree trunks, branches, or hollows in trees
- talus (piles of rocks in the mountains)
Look for bats swarming near a roost before dawn.
If you think a human structure, tree or area of talus might have bats roosting, you can also take a look from a distance just before dawn to see if you can spot bats swarming around a roost site. Bat swarming is when several bats circle around a building or tree or other type of roost site before returning to their roost. If you see bats flying at sunset, then you may be able to locate their roost just before dawn by walking in the direction from which they came and looking for swarming bats.
Don’t disturb roosting bats! Avoid entering places where bats may be roosting.
In spring and summer, a roost offers a safe place for female bats to give birth and rear young. If disturbed at this sensitive time, female bats may abandon the roost and their young. People who go into caves, mines and other bat roost sites may also spread a fungus called White Nose Syndrome that could kill bats by bringing it in on their shoes, clothing and gear.
Don’t share information, including photos, about roost site locations on social media.
Bats may abandon roost sites that are visited by too many people, and people who dislike bats may vandalize roost sites and kill bats.
Tips for spotting bats emerging from or swarming near a roost:
- Come 30 minutes early! To spot bats emerging from a roost, set up and be ready at least 30 minutes before sunset. Bats usually come out before it’s completely dark. To spot bats swarming near a roost, set up and be ready at least 30 minutes before sunrise. Bats usually swarm near roost sites just before dawn.
To find out the sunset and sunrise times at your location you can enter your nearest city and the word ‘sunset’ or ‘sunrise’ into Google, or visit www.timeanddate.com/sun and search for your nearest city.
- Do your survey between May and September. This is the best time to see groups of bats leaving roost sites in the evening, or swarming as they return to roost sites in the morning. At higher elevations (where winter lasts longer), the best time to see bats is from late June to early September.
- Do your survey when the weather is good. Bats may not be active on cold nights, or nights with heavy wind or rain. It’s best to do your survey when it is 50°F or warmer with light wind and no rain.
- Watch all of the places where you think bats could enter or exit the roost. Before your survey, try to guess where bats might come out of or enter the structure, tree or talus, and recruit some helpers to watch all of the places where you think bats could exit or enter the roost. Some structures, trees and talus may have multiple areas where bats can exit and enter.
- Position the night or dawn sky in the background if possible. This will help you see the bats.
- Do not shine lights at the roost. This may prevent bats from exiting or entering the roost.
- Be quiet. It’s a good idea to be quiet during bat emergence or swarming.
- If you are looking for bats emerging from talus watch from an area of solid ground near the talus. Talus is unstable and dangerous to walk on.
Prepare and bring the equipment you will need:
- Review the health and safety guidance before doing your survey.
- A smartphone, OR a clipboard and writing utensil
- An online or paper survey form that you will use to report your observations to Colorado Bat Watch. Get your forms here.
- A headlamp to use to find your way to and from the area where you plan to do your survey.
- Binoculars (optional)
Share your observations with Colorado Bat Watch.
Check out the FAQs or email us at firstname.lastname@example.org.
If you observe a sick or dead bat, or a bat that is active in winter, please report the sighting to Colorado Parks and Wildlife as quickly as possible, by calling 303-291-7771 or emailing email@example.com. If a bat is active in winter it could mean the bat has White Nose Syndrome. For more information see our FAQs page.
These instructions were adapted from protocols and instructions developed by bats.org.uk, georgiawildlife.com, and Rob Schorr.