Thanks for posting the site for building a bat house Roger. I have been meaning to make some for some time now.
When we moved into our house, I opened an upper cupboard that had the vent for the stovetop running through it. A brown bat had made it's way into a container in the cabinet, from the vent outlet outside, and had flattened itself down into a comfortable position, inside the container. I stood there for a minute thinking to myself, what the hell, before I realized what it was. I grabbed the container and put it outside with the bat flapping inside.
The wife was not impressed, because it brought up the memory of the bats flying around her bedroom while she was sleeping, with the door closed. I heard her screaming after waking up, and I had to seal the door off that went to the attic where they liked to roost.
But we do enjoy watchnig the bats at dusk out on the deck. They have been back for a few years now since their downturn.