Nuisance Species: Bats
There are 10 bat species commonly found in Ohio and they are all insectivores, meaning they eat insects. Bats are the only major predator of night-flying insects and they help farmers by saving them billions of dollars a year on pest control. Bats are usually able to exist near human homes without making their presence known. However, with decreasing amounts of habitat available for bats (e.g., trees being cleared), bats may find their way into man-made structures. Bats use existing openings (cracks as small as 1 ¼ inch by 3/8 of an inch) to enter buildings or to roost in attics. To remove unwanted bats from a building, you must place an exclusion device over their main entrance and seal all other holes. Exclusion devices allow bats to safely exit the house but keeps them from getting back inside. After leaving the device up for several days and ensuring all bats are gone, the device can be removed and the last exit sealed.
In order to protect flightless bat pups, it is unlawful to perform an exclusion between May 16-July 31 if there are 15 or more bats inside a structure. In situations where human health and safety is at risk, a property owner/designee may seek written authorization from the Chief of the Division of Wildlife to perform an exclusion during the restricted period. Before applying for authorization, the property owner/designee must inspect the property for bats and perform two bat watches at dawn or dusk at the structure within a 7-day period. To apply for exclusion authorization, please complete and return a Bat Exclusion Authorization Application (Please contact ODNR Division of Wildlife customer service at 1-800-WILDLIFE (945-3543) or email@example.com for more information).
Occasionally, a bat may get into your house. If one does, there is no need to panic. Open a window or exterior door, and close interior doors, confining it to one room if possible. The bat will leave as soon as it locates the exit. If the bat continues to stay in the house, we recommend calling a professional to have it removed. If you decide to remove the bat yourself, the “shoebox method” is the best way to do that without physically handling the bat. Grab a shoebox, or some sort of sturdy container and place it over the bat, whether on the floor or wall. Then, slip a lid or piece of cardboard under the box. Take the box outside and place it up against a tree so that the bat can crawl out onto the tree as bats cannot fly from the ground. This method works well in the spring, fall and summer, but if it is the middle of winter, it is advised that you contain the bat in a box with a small blanket or towel and call a local wildlife rehabilitator. Rehabilitators that can handle bats are the rabies vector species certified rehabilitators listed on our orphaned and injured wildlife page. You should never handle the bat with bare hands, so wear the thickest gloves you can find, preferably leather or fireplace gloves. Then, determine how the bat got into the house and seal the opening(s).
If you have a colony of bats in your house, normally in the attic, it would be good a time to call a professional company to come to your house and carry out an exclusion. The most popular and recommended form of exclusion is a one-way door. This allows for the bats to leave on their own, as they would to forage at night, and then they would not able to get back into the house. When installing a one- way door, it is advised that you also bat-proof your house. Bat-proofing is a way to close off all possible entrances in a house. Due to the small areas that bats can fit into, it is best to have a professional do this.
All bats in Ohio are declining and protected in some form or another and cannot be intentionally harmed. Therefore, you should not kill the bats in your attic as it is illegal. However, they should be removed due to potential health concerns for humans. Feces from bats and birds can hold a lung infection disease known as histoplasmosis. For this reason, it is advised that after excluding the bats, the attic is thoroughly cleaned with proper protective gear. For more information about histoplasmosis, you can visit the Center for Disease Control website.
As previously mentioned, a large reason that bats make use of buildings for roosts is due to lack of otherwise available habitat. The Division of Wildlife strongly suggests placing a bat box up outside to replace the lost habitat of an attic. This will not only provide additional habitat, but it will prevent bats from trying harder to seek entrances in your home. Bat houses should be placed approximately 15 to 20 feet (no lower than 10) off the ground on a tree with approximately 7-9 hours of daylight. Bat boxes should have dark stains in order to soak in as much of the sun’s warmth as possible. These bat boxes are easy to put up and can provide a home for more than 100 bats. If you would like to put up a bat house in your own backyard, you can visit the Bat Conservation International website.