Lake & Cabin Bluebird House features an insulated green metal roof and  9/16" hole size. The easy open front makes it easy to clean and the predator guard protects the nesting birds.  This ornithologically correct, Bluebird House is designed specifically for bluebirds. Durable wood construction is assembled with screws (not nails) to withstand temperature changes. Ideal for the Eastern, Western, and Mountain Bluebird. Designed with a 9/16th-inch hole is ideal for western or mountain bluebirds. . Featuring an easy open front panel and a  1/2" air ventilation gap is provided at the top as well as a drain hole at the base. Specifically designed entrance holes and predator guard discourages other unwanted species from invading the nesting area. Fully assembled and ready to mount.