Cut the sides of the birdhouse to 4 inches high and 6 1/4 inches wide. Make a 45 degree bevel on the top.
Build the front of the license plate birdhouse 7 inches wide by nine inches tall. Create a peak that is at a 45 degree angle.
Create a hole on the front for entrance into the birdhouse. Use the 1 1/8 inch drill bit and drill the hole 4 inches from the bottom.
Drill a hole for the perch. Drill the hole 1 inch below the entrance hole using the 1/4 inch drill bit.
Make the back of the license plate birdhouse. It should be 7 inches wide by 9 3/4 inches tall with a 45 degree peak. Trim the bottom of the birdhouse to 6 1/4 inches wide by 7 inches tall.
Assemble the pieces together using galvanized nails or screws. Only 1 inch of the bottom will jut out for a railing. Apply a weatherproof sealant.
Fold the license plate in half to crease it. Lay it on top of the birdhouse and nail or screw it down so it will resemble a steel or metal roof.