Small Brown, Large Brown

Photo by D.Fletcher
Photo by Bladeflyer
Wisconsin is home to eight species of bats. The total bat population in Wisconsin is estimated by our DNR to be around 2 million. The two most populous species by far are the large brown bat and the small brown bat. While most bats spend the majority of their lives living in caves around the state, some make their way into houses and take up residence there and even start to build colonies if they are not controlled.

The most humane method of control and the only one sanctioned by the Wisconsin DNR is a process known as exclusion. A bat exclusion involves very detailed inspection of the exterior of the house to find the hole or holes the bats are using to move in and out of the building. Once this hole is located we install a one-way exit device that lets the bats go out like normal, as they do almost every night during the summer months; but when they try to get back in, they cannot figure out the device and they soon give up trying that hole and go in search of another. That is why the exclusion process also requires further inspection of the entire building and sealing of all gaps 3/16 inch or larger that can let bats back into the house. This entire process takes on average between 1 and 2 hours depending on the size, construction, and condition of the house. Once this process is completed, Prompt Action can guarantee the work will keep bats out for 2 years. As long as there is not storm damage, new construction, or squirrel or other pest damage that opens a hole big enough for bats to get in. If you think this may have happened we can re-inspect and seal for a small percentage of the price of the original job. If for some reason we fail the first time to get the bats out, we return as many times as it takes in the next two years to solve the problem. After 13 years doing bat exclusions in Wisconsin, and over 2000 homes excluded, we can say that we have never failed to get the bats out of a house, and that you can be confident that we have the experience and expertise to do the job right.

Now, because bats are listed as Threatened by the Wisconsin DNR, there are certain guidelines we follow when doing a bat exclusion. We do not knowingly harm or kill a bat. We can do bat exclusions unrestricted any time before June 1 or after August 15. This period is when the DNR believes bats are in their maternity period- having babies and nursing them. Threatened status means we have to do all we can to not let the babies die as well, so the regulations state we can only do bat exclusion during this time if the customer has serious health and/or safety concerns.