William Bagwell wrote:
How long has it been up? Current consensus is that if it fails to attract bats
after two years try moving it to a different location. ...

My bat story:

When we remodeled, many years ago, some siding and trim was removed from
the house, giving a few very small openings into the attic. The bats
found those openings almost immediately and took up residence. Which we
didn't realize until we finished the remodeling, closing up the
openings, and forcing the bats to exit the attic through the crack under
a door, into the house.

Intending to seize the opportunity to have a bat colony, I made a bat
house and mounted it on the side of our house. It took them 11 YEARS to
take up in that bat house! I guess that my bat house just didn't have
the appeal that the attic did.

Bob