Here is a link to the pdf web.archive.org/web/20230804012701/nestboxbuilder.com/pdf/peterson.pdf. Another link www.familyhandyman.com/project/build-a-bluebird-house/ and the archived link in case that website goes away. web.archive.org/web/20230324010210/www.familyhandyman.com/project/build-a-bluebird-house/
Peterson has always been my choice. I did increase the standard 1 1/2 x 3 1/2 frame to a full 2 x 4 .The extra width seems better.
Brooding doors don’t have to be on the bottom and actually makes the birds more vulnerable to predators.
What's the link for this publication?
Here is a link to the pdf web.archive.org/web/20230804012701/nestboxbuilder.com/pdf/peterson.pdf.
Another link www.familyhandyman.com/project/build-a-bluebird-house/ and the archived link in case that website goes away.
web.archive.org/web/20230324010210/www.familyhandyman.com/project/build-a-bluebird-house/