Owl Boxes. This site is from England. In Michigan we have the screech owl, which requires a 3 inch hole. Box should be 10 to 30 feet off ground. Box must be water tight. We need owls to keep those little pesky chipmunks and such in check. Think owl! in your backyard.
Nest Box Placement - Because different species of birds prefer different kinds of nesting habitat, the vegetation surrounding your box will play a role in determining which species will nest in it. Remember: right box, right place. - Need help placing your boxes? Look here: http://nestwatch.org/learn/all-about-birdhouses/nest-box-placement/