Start with the right housing! Hygienic, recycled plastic has the requirements bluebirds need--proper ventilation, floor size, entry hole and predator guard. And it's attractive and durable. It has a wood-grained finish, sturdy all-screw construction and it's completely impervious to weather. A clean, safe place for bluebirds to raise their families! Pre-drilled for mounting, cedar brown and green recycled plastic. Entry hole is 1-9/16 inches, house measures 7-3/4 x 7 x 12-1/2 inches high. Made in the USA.