With the warm summer nights and the increase in the bats favorite foods, i.e., bugs, mainly mosquitoes, however they eat moths and beetles as well.
Bats like to live in attics, chimneys, under siding, behind shutters, under shingles, inside of walls, in woodpiles, hollow trees, really they can be anywhere. The like their homes or ‘roosts’, hot and dark. Bats can enter a property from tiny little cracks, gaps or holes, they only need ¼ an inch to enter!! That is very tiny.
Here is a link to Maryland’s Department of Natural Resources, this page talks all about bats and how to get rid of them, the best times of year (now is not the best time, they are having their pups, and how to keep them out.
A couple of years ago, my friend rented an apartment in an old building in Anne Arundel County. The apartment was huge, however very inexpensive, there turned out to be many reasons for the cheapness of the rent, however bats in the unit was one of the problems.
The first evening we were in the kitchen putting things away, we heard a squeaking noise, we both turned to the living room, flying at us was a bat! We had the door open and I guess it was time for the bat to go out and get dinner. My friend and I both ran for the open door, pushing the other out-of-the-way. It took us both a while to get the nerve to go back into the apartment; we ended up just locking the door and hoped everything would be better the next night.
The next day, she spoke to the landlord, he told her that he did not think it would happen again, and not to worry. We took him at his word, huge mistake. A couple of nights later again we saw a bat in the unit, well it was a couple of them, we ran out and stayed out to the next morning.
When we return in the morning, after a quick Internet search on how to keep bats out. We started looking for holes and gaps, filling and plugging them as we went along, till we got to the closest in the living room. We opened this extremely large closet and happened to notice brownish things on the back of the closet doors. When we looked closer it was bats! Again she and I could not get out of the unit fast enough, it must have been hilarious to watch us.
The neighbors heard us and came out to see what was the matter, we explained there were bats in the unit, the other tenants said they have bats in their units all the time. My friend never did actually move into the unit.