University of Wisconsin - Extension

Halloween wouldn't be the same without frightening images, such as bats.

But bats have an undeserved bad reputation, according to Scott Craven, University of Wisconsin-Madison/Extension wildlife specialist.

"Few animals are as misunderstood as the bat," says Craven. "Much of the fear they elicit is unwarranted and based on misconceptions."

For example, Wisconsin bats do not suck blood. The vampire Bat does, but is not found within 1,500 miles of Wisconsin. Bats do Not swoop down into women's -- or men's -- hair. And, most bats are Not rabid.

"Bats are interesting animals," Craven adds. "They are highly beneficial because they eat tremendous numbers of insects, including mosquitoes."

Still, there are good reasons why people may not want them In attics or outbuildings. Their droppings and urine are offensive, and their high-pitched squeaking can be annoying.

Wisconsin has eight species of bats, five of which spend winters here, hibernating in caves, shafts, crevices and buildings. Since bats have excellent homing abilities, they return to the same summer or winter quarters year after year, Craven says.

When working to control bats, Craven suggests non-lethal control measures. One or two bats in the house may mean they came in through an open window or chimney. But their presence also could signify a colony of bats in the attic or walls.

"If you find a colony of bats in your house, the only long-term solution is to `bat-proof' the building," explains Craven. Seal all bat entrances using screening, hardware cloth,

Steel wool, lumber, cement, caulking compound or some other material appropriate for the size of the hole.

Bats can fit into cracks that are only three-eighths of an inch, but they cannot gnaw or reopen old holes, unlike rats or squirrels. "Do not seal bat openings until the bats are out of the attic," suggests Craven. "This means waiting until an hour or so after sundown when bats will be feeding or until November, by which time most Wisconsin bats move out of attics to winter quarters."

If bats remain in attics during cold weather months, there's nothing that can be done until warm weather returns to the state. Once bats choose a location to hibernate for the winter, its virtually impossible to find them and remove them, adds Craven.

Avoid sealing openings in June and July when flightless Young bats are likely to be present. Attic openings can be located by watching for bats to fly in and out at night, determine where light enters a dark attic on a bright day, or put a light in the attic on a dark night and look for light from the outside.

If homeowners find several bat openings, they may wish to Seal all but one or two to allow bats to adjust to the restricted access. Bats trapped inside must be captured and released, or they will quickly starve.

One-way excluders help eliminate the need to capture bats. "When properly mounted over an access hole, the device allows bats to leave the building but prevents them from getting back in," Craven says.

Rather than controlling bats, many people in Wisconsin are attracting them by building and erecting bat houses. "Bats are interesting to watch, help control pesky insects and benefit from our help as much as any other group of animals," adds Craven.