The Bat Guys came and installed bat doors. It looks like a piece of window screen folded into a tube, and it may well be just that, but I will do anything to avoid being awakened by a bat flying around my head again. These are the opposite of a roach motel. Bats can check out but they can't come back in. The guys also sealed up the holes through which the bats were entering the house. They'll come back in 30 days to remove these doors and seal up these last few holes.