Blue jays nest in the crooks of large tree branches 10 to 30 feet above the ground. They build their nests with thin, freshly broken roots and twigs, and sometimes patch them together with moss and mud. To attract blue jays to your birdhouse, mimic the jay's natural preferences, and provide food nearby.
Blue Jays Prefer an Open Platform
A closed birdhouse with only a small hole for an opening will attract birds that nest in tree cavities, rather than in the branches. Blue jays prefer a large open platform to an enclosed box. Build a platform with a base measuring approximately 8 inches square, and construct a slanted or gabled roof over the top to keep the nest out of direct sunlight and relatively dry.
Materials for the Platform Birdhouse
A platform birdhouse for blue jays only requires three sides -- it needs a platform, a roof and a rear wall. Shallow walls on the left and right sides can be added to make the construction more sturdy, but make sure they don't obstruct the blue jay from entering by the side of the platform. You need an 8-inch-wide board that's at least 4 feet long, a saw to cut the board into usable segments, galvanized screws and a drill to make pilot holes for the screws.
Constructing the Platform Bird House
Cut two segments from your board that are 8 inches long and one segment 11 1/2 inches long. To make side walls for your platform, cut two segments to be 8 inches tall and 2 to 3 inches wide. Cut across the tops of both side pieces at a 45-degree angle so the roof will be angled down. Before attaching the pieces with galvanized screws, drill pilot holes so the screws will not split the boards. Attach the two 8-inch boards at a right angle to each other, creating a rear wall and bottom platform. Attach the two side pieces to the rear wall and platform so that the 45-degree cut slopes down from the rear wall. Screw the remaining 8-inch-wide board to the side boards to form the roof. It should be long enough to cover the entire platform.
Attracting Blue Jays to the Birdhouse
Blue jays usually nest at least 10 feet off the ground, so place your bird house at least that high in tree or on a pole. Small piles of thin sticks and dug-up tree roots provides blue jays with the nesting material they want. Place these small piles near your new birdhouse to provide easy availability of building material, which will encourage blue jays to use the site. You can also put some of their favorite foods on a feeding platform nearby, like suet, in-shell peanuts and acorns. As the birds return time and again to the resources you provide, it increases the likelihood that your nesting platform will be found and used.