About a year ago I sent some guys to work in and older lady's crawl space. They called all frantic because when they moved some insulation, bats came out at them. Checking into getting rid of them, I got quite an education. It seems they are protected and a special license is required for their removal, as well as needing a permit for each instance of relocation. Note I said relocation, you cannot harm them. At least in Illinois that's the case. The other option the conservation department gave me was to wait for them to leave on their own, then seal their way in.