I had a question about how to build a bat house. They are really simple to make. It takes a rigid back board of about two feet wide by 14 inches long. No need to be precise. Whatever scrap wood you have around should do it. (For instance, the one I have has three boards to make up the solid front.)
The back board should be one inch longer than the front. Cut the tops of each board at an angle to allow you to put a little roof on it if it is exposed to rain. Or square it off if you plan to hang it under an eve or breezeway or some type of shelter. The front board should be shorter than the back board at the bottom.
Staple a piece of screen to the inside of each board before sandwiching them together with a one by one piece of scrap on each side. The screen gives the bat some purchase. Screw the three thicknesses, front, back and spacer together. Roof the top with left over shingles glued to a flat, thin molding board, screwed onto the top, and you are ready to hang it. The photo below shows the bat house from the bottom, looking into the screened insides. This size house will hold about 80 bats and give the flies and mosquitoes notice to move on to other areas.
Now, how to attach one to the new RV. Hmmm! Just kidding.