Bats in the belfry? New rules regulate their eviction

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Marcia Nelesen
December 8, 2014

JANESVILLE—Chad Lette wasn't surprised the 162-year-old home he was buying on Court Street had bats.

What did surprise him was the new-fangled way to get rid of them.

Officials at the state Department of Natural Resources, alarmed by bat mortality rates caused by white-nose syndrome, in the last several years have issued new rules and regulations to protect bats, several species of which are on the state's threatened list. The species include the little brown bat and big brown bat, two types that might find their ways into a home.

“Because of white-nose syndrome, we saw a real need to protect the species we had,” said J. Paul White, DNR mammal ecologist.

The fungal disease attacks the skin tissue of hibernating bats, creating holes in their wings and skin membranes.

The regulations restrict how homeowners can get rid of bats roosting in their attics.

Bats tend to return to the same sites each summer, so killing bats that get inside isn't the answer, White said.

Sealing a home is preferred.

In the past, pest control workers or homeowners simply closed any small holes along the roofline through which a bat could squeeze. Any bats trapped inside died.

Now, homeowners are required to install one-way exits and leave them there for about a week. Bats can leave but can't get back in.

To protect bats, the DNR does not allow homeowners to rid their home of bats from June 1 through Aug. 15. One-way doors installed then would prevent mother bats from getting back inside to care for their young.

John C. Davis of Blue Pest Control and Home Services in Janesville figured Lette's home served as a roost for two to four bats.

Davis is on the board of directors for the Wisconsin Pest Control Association and meets with DNR representatives regularly.

Davis has been getting rid of pests in homes for 15 years.

“In the past, you just started sealed it up, and anything in there would die,” he recalled. “Or you would net it and release it.”

Work is allowed during the exclusion period only with permission from the DNR, he said.

The most important step in clearing a home of bats is the initial inspection, Davis said.

He uses a portable lift so he can scrutinize a home's entire roofline. A common place of entry is under the eaves at corners, where water rots the wood.

Bats can get through a gap as small as a quarter of an inch in diameter, Davis said.

“You can't see it from the ground looking up on a ladder,” Davis said.

Sometimes, you can also see light through gaps if you are inside the attic looking out. But other times, the holes are obscured by insulation. Then, you must look for holes through the insulation about the size of hamster tubes that the bats have tunneled, Davis said.

Homeowners can watch their homes just before sunset, noting where the bats leave the building. Sometimes guano, or bat poop, can be found on the ground under the main access areas.

Once the entries are identified, Davis dons a protective suit, respirator, gloves and boots.

He nets and releases any bats inside. In the winter, Davis takes hibernating bats to a bat hibernation area he built so they can finish their hibernation before releasing them in spring.

Next, he mists any guano to keep the dust from rising.

The guano is relatively harmless, but it supports a bacteria called histoplasmosis that causes infections in humans.

Then Davis closes the holes. He removes contaminated insulation and replaces it with new.

It took two men about three days to finish the Lette home, Davis said. Cost is about $5 a square foot, so the average attic of about 600 square feet costs about $3,500.

White from the DNR urges homeowners to be neighborly even though they have just evicted the bats from their homes.

He suggested placing bat homes near the original entryways so the bats continue to return to the area, eating the insects that trouble humans and agriculture.



J. Paul White, mammal ecologist at the state Department of Natural Resources, really loves bats.

When The Gazette asked him for a picture of himself to run with this story, he asked if he could send a picture of a bat instead.

White urges residents to change their views about the misunderstood mammal.

Bats pollinate flowers and disperse seeds for countless plants. They also eat the bugs that attack Wisconsin's valuable agricultural crops and that bother humans. One bat eats 1,000 mosquito-sized insects in an hour.

Don't worry about your hairdo around bats, White said.

“I've been around thousands of bats and never had one in my hair,” he said.

If bats are flying around your head, they are actually doing you a favor by eating the insects.

Rabies in the population is relatively low, at about 0.01 percent, and bats with rabies are easy to spot because they are acting so strangely.

So think twice before you pick up that tennis racket to kill one in your home, he pleaded.

Relax, he advised.

Isolate the bat as well as you can and simply open the doors and windows and let if fly out on its own.

If it lands on the wall and isn't moving, trap it in a box and slip a piece of paper or cardboard between the box and the wall.

Instead of tossing it out the door, lean the box against a tree to give the critter a while to get its bearings, he said.

For more information about bats and the bats exclusion program, go to dnr.wi.gov/topic/WildlifeHabitat/Bats.html

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