Premium Bluebird House manufactured with heavy-duty lumber for superior weather resistance. Side tilts open for inspection and cleaning. 1.5" Entrance Hole. Enjoy the beauty, songs and behavior of your very own Bluebird family in your own backyard! As our environment becomes more dangerous each year, it becomes increasingly important to provide houseing for Bluebirds to birth and raise their young. Heath Bluebird Houses have been a long-time favorite of Bluebird enthusiasts and have graced America's backyard for decades.