After researching the proper dimensions for bluebird houses, these were the most consistent I could find.
Basically they are a 5 ½” square, an overall height of 15”. The hole must be 2 1/4” from the top of the front and 1 ½” diameter.
I added an extension block and the aluminum plate to stop squirrels and other predators from enlarging the hole and reaching inside.
I used cedar for the main components and a secondary wood for the mounting plate. The door pivots on a ¼” dowel and is secured with a couple galvanized nails which are left extended for easy removal. The house must be cleaned out after each nesting season. Mount your new birdhouse 4 – 6 feet from ground level and preferably with a tree nearby.
Right click to download or left click to open: Bluebird House Plan