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.
I believe the bluebird is one of the most beautiful birds to observe and if you can attract them you will can enjoy their beauty as well. Happy bird watching!
Click to download: Bluebird House Plan