Pennington Red Cedar Bluebird House is made out of Eastern Red Cedar, nature's renewable resource and is naturally resistant to weather. Perfect for Eastern Bluebirds! This is a classic style Bluebird house that is perfect for getting Bluebirds to nest in your yard. The front opens for easy viewing and seasonal cleaning. Air vents allow for proper air ventilation through wall and floor openings. It is recommended the clean before each breeding season to promote the health of the birds. The innovative design can be installed with a pole mount or flush mount to any tree or post. Size of opening, at 1.56", meets Bluebird Society guidelines.