This note comes to you from "across the pond". Our group - THE NORFOLK BAT GROUP is based in the county of Norfolk in England, UK.
We have a membership of 300+ people who are interested in bat conservation and have also been experimenting with different bat box designs for some of our dozen bat species - looking at your pages and links it seems we are trying to re-invent the wheel !
You can see some of what our group gets up to by visiting:-
in addition to experimenting with different types of bat boxes we also manufacture a "bat hibernation brick" which you can also see illustrated on our web pages with details of how it is used. These have been exceptionally good at attracting hibernating bats to underground sites with up to 7 bats of 3 species using a single unit. Some 3,500 of these "Norfolk Bat Bricks" have now been placed at various sites within the UK.
Its good to share experiences on bat conservation - they deserve our help and encouragement.