Bluebird houses are nesting boxes for bluebirds and swallows. The houses are solidly built using construction grade hot glue, nails and screws. All roofs are removable for seasonal cleaning by removing one front locking pin. Basically the only differences are the cork trim and the type of wood used. Bluebird houses have a flat back and mount on a post top or side, or on the side of building or tree. Traditionally you see them with a flat roof, but mine have a peek that allows the roof to be easily removed. A blurbird house is easy to recognize because there is larger hole and no perch.