Both little brown bats and big brown bats are very common bats in Ontario. They’re known to invade structures and will usually infest a home by entering through holes and cracks around the soffit, fascia, roof flashing, or vents. Holds that are ¼ of an inch or larger are potential entry points for these bats. Once these bats are inside of your home, they’ll wind up roosting in your attics, wall voids, chimneys, and other such areas. Bats can be a health risk by contributing to mold problems and are also known carriers of rabies, ticks, and mites