Bats were entering at a transision between like a bay window and the main roof. Litterially slipping under a shingle. When I saw approx where they were coming out I put a next camera on the roof. They were slipping under a spot about the size and thickness of a butter knife handle!!! They slipped in and out almost like magic. Local "bat expert" wanted $5000 just to tell them to leave LUCKILY there is a bunch of info online. The camera on the roof was the best investment/method. The CRAZY part is you can't just seal them in. I had to wait till 9:30PM every night when the left (about 4 of them) like clockwork. Then go up on the roof and cover/block that spot. Opened it back up in the morning. Had to do this for about a week to make sure they all wetre out and had left. Then sealed for good. Then paid almost $1000 to have strips of Z shaped metal mesh over the edges of all the ridge vents. Guess that the most common place for them to come and go. WHEW. What a learning curve that was.