What should you do if you find a bat in your home? According to the Massachusetts Division of Fisheries and Wildlife:
The most common entrance ways for bats entering a home include an unscreened attic vent, a crack or separation where the chimney meets the house, a hole or crack under a rotted eave, rotted window sills or loose-sitting screens, chimney flues, pet doors, an open cellar hatch (bulkhead), where pipes or wiring meet the house, or gaps in loose or warped siding.
Fortunately, a single bat can usually be dealt with quite easily. Stay calm and do not chase the bat. Keep pets and children away from the bat. It will NOT attack you or become tangled in your hair, although it may be disoriented and flutter by close to you. The best action is to open a window or door in the room containing the bat, close off the rest of the house, and block the space under the door with towels. Turn off or dim the lights as bright lights disorient bats. A flying bat will usually circle the room several times until it locates the open window and flies out. If it is nighttime, it is usually only a matter of a few minutes before the bat leaves the house. If it is daytime, the bat should leave within an hour after dark, as long as the weather conditions are appropriate (above 50 degrees F, no rain or high winds).
If a bat has landed, it can be assisted out of a house in several ways. For a bat on a curtain or wall, place a jar, coffee can, kitchen strainer, or small box over the bat, carefully working the bat into the container, and then slip the lid on or cover the box quickly with a piece of cardboard. A bat on the floor can be covered with a towel, picked up within the towel, and then released outdoors. Another method is to put on thick work gloves and simply pick up the bat and release it outdoors. Do not use thin gloves and never pick up a bat with bare hands. No species of bat that occurs in Massachusetts can bite through a thick towel or leather gloves. Whatever method is used, the bat will likely open its mouth and squeak loudly when handled; don't worry. Take the bat outside to release it, preferable after sunset. Tilt the container away from you and allow the bat to climb onto a tree branch, windowsill, or other surface at least 4 feet above the ground.
Bats found in buildings during the winter may not survive if released outside in below-freezing temperatures, high winds, or heavy rain. If you find a bat in any of these conditions, contact a local licensed wildlife rehabilitator.
If a bat seems injured, contact a local licensed wildlife rehabilitator. If you find a baby bat, wear thick work gloves to gently pick the baby up and place it as close as possible to the potential colony location (i.e. bat house, attic, eaves, barn, shed, etc.), or off the ground and in a tree. If it is a baby, the mother bat will return for her pup.
If anyone has had direct contact with a bat (i.e. bite or scratch), or if a bat is found in a room with a sleeping person, the bat should be safely captured and not released. Wash the affected area thoroughly with soap and water, and immediately seek professional medical advice. Contact local health officials for assistance in evaluating potential rabies risk and submitting the bat to the Massachusetts Department of Public Health (DPH) for rabies testing. Testing is done at the DPH office in Jamaica Plain, Massachusetts (617-983-6800 or 617-983-6550), and submission is usually coordinated by the person's municipality.