True, owls naturally nest in trees and barns, however, it is not ideal for us humans to have them too close. The Santa Clara Valley Audubon Society (SCVAS) has some good information regarding owls, their nesting habits and how humans can help or hurt. Someday, we hope to be able to point you to our blog for this information. Until then, you can get it from their site. Click on this link or go directly to the following site to see the publication.
This .pdf has some great information on the barn owl, including breeding cycles and life style, with a few pictures, too. This is also where we found the specifications for a barn owl box. Everything you need to know on how to build it so that predators are not likely to get in, but if they do, the owl will be in the offensive position and not the defensive, is on this site. The SCVAS also provides further resources in this publication for those interested in going a step further in their research.
We invite anyone who would like to share their knowledge or opinions on these matters, in addition to any experience one may have, to do so on our Facebook page. Look for the link below or search for @LoxahootLife.