This bird house with a 4" x 4" floor is suitable for most common backyard birds including bluebirds, titmice, swallows, nuthatches, chickadees and wrens. The 1 1/2" hole is protected by a slate predator guard to ward off pesky squirrels. Measures approximately 12 1/2" h x 6" w x 8 1/2" d. Made in Maine from eastern white pine.