[Mobile Master Tech]

I had to remove a bat infestation in my eaves in a previous house. I learned you first have to find out where they are coming in and out by watching quietly at dusk. Then, seal off any other potential entry areas before exclusion. To exclude them, cover their entry/exit with a hanging sheet of clear plastic(so you can confirm their exit) at least 2 ft against some surface (the house siding in my case). They will come out and work their way to the edge of the plastic to fly away, but can't find their way back under that to return, since they want to go to their usual entry point, now covered.

Bat houses have to be warm and dry with 3/4" or smaller spaces between the walls/dividers. If it is too hot during the day or too cool at night, or doesn't smell right, or is too wide, they will go elsewhere. IIRC, the book I read said to change the positioning on the same tree (changing the time of day for peak temps) after a few weeks if it doesn't attract them. If that doesn't work, start moving the houses to different locations and try again.