Bats in the belfry?
Take a deep breath, and read on.
By Eileen Dowd Stukel, Wildlife Diversity Coordinator, SDGFP and
Joel Tigner, bat biologist with Batworks in Rapid City.
Fall is when many birds take flight for warmer climates and some mammals prepare for hibernation. It is also a good time to safely and humanely exclude bats from your home.
Homeowners may panic at the sight or sound of bats in the attic during the summer. Bats are often painted with a broad brush of negativity because of their unique appearance and lifestyle. Bats are not rodents. They give birth once a year and generally only to a single pup. They don't make or enlarge openings in buildings or build nests.
Bats feed exclusively on night-flying insects, many of which are agricultural or forestry pests. Habitat destruction and direct persecution have put many bat species in harm's way. Even after hearing the positive spin on bats, you may not love them, but they will benefit from a little tolerance on your part.
Two common complaints involve a single bat that finds its way into a living space and a group of bats living in an attic. An individual bat is often a young bat that has crawled through a hole, become disoriented, and cannot find its way out. If there has been no physical contact with the bat, try to isolate it in a room with an open window or door to the outside, and the bat will usually find its own way out. If you must capture the bat, always wear gloves, wait until the bat lands, place a small container over the bat, slip a piece of cardboard over the opening to seal it, and carry the bat outside for release. If you are uncertain whether there may have been physical contact with a person, seek guidance from health officials and hold the captured bat for possible testing.
In the second scenario, a homeowner sees or hears bats in the dwelling and wants the bats out - immediately! Armed with a tennis racket and a spray can of some kind, homeowners wage war on bats or call a pest control company, expecting immediate successful results.
The most common bat species in South Dakota form maternity colonies, composed of a group of females, each with their single young. Maternity colonies often use the same roost from year to year, adding to a homeowner's challenge to finding a quick, easy solution. If your home hosts a maternity roost, it is difficult and even unwise to evict or kill the tenants until after the pups can fly. Killing adults or closing entry points during the summer may make the situation worse. Young bats awaiting their mothers' return may leave the roost in search of the adults, possibly traveling into your living space. A group of trapped bats dying within the structure can produce an unpleasant odor inside the home.
Poisoning is a dangerous and irresponsible course of action. Bats are mammals, and poisons that kill bats may harm people and their pets. Poisons may not kill all the bats, leaving sickened bats to fly away from the roost, become grounded, and be retrieved by area children and pets. Poisoning also does nothing to address the fact that bats were gaining access to the structure in the first place, and the problem may reoccur in the future. In addition, no poison is legal for use against bats in South Dakota.
Don't assume that pest control companies are knowledgeable about safe, humane, and effective bat exclusion. Any method that involves killing adult bats at a maternity roost during the summer should be questioned.
Exclusion is the best way to deal with an unwanted bat roost. It can be accomplished without harming the bats by following some simple techniques and guidelines. IMPORTANT - In South Dakota, conduct your exclusion before mid-May or after September 1 to avoid trapping young bats or destroying a maternity colony.
First, identify the bats' primary point of entry into the structure by watching for their emergence around sunset. Then check the rest of the structure, looking for potential entry points that the bats might use once they are excluded. Before the exclusion, seal all of these holes, leaving only the primary entry hole. This can be done at any time of the year. Attach an exclusion device (pictured below) over this last opening. Leave it in place for about a week of good weather giving all of them the opportunity to get out. At this point, remove the device, permanently seal the hole, and you've solved your problem. A simpler plan is to wait until the bats have left for the winter and seal the last opening on a nice day after some cold weather.
Consider building and placing a bat house as an alternative roost to help bats and keep these pest-eaters in your area.
An illustration of the use of a temporary cone in excluding bats. The final entry/exit hole is identified in the photo on the left. A cone-shaped item is temporarily taped across the hole. Note the opening at the small end of the cone, which allows bats to exit, but prevents them from reentering. Leave the cone in place for 4-5 nights of good weather, which should allow the bats to leave. Once all bats have exited, the hole is permanently sealed. Remember: Only use this technique during the safe dates before or after the maternity season to avoid trapping young bats inside the structure. Photos by Joel Tigner
For more information about bats and bat houses, visit Bat Conservation International's website:
For more information about bat exclusion in South Dakota, visit the South Dakota Bat Working Group's website: