Bluebird houses: attract not only bluebirds but tree sparrows, wrens, chickadees, and (dolt!) house sparrows. Our bird houses are available at materials cost ($17) with a 7-ft post. They include a wire Noel guard but not a swinging stovepipe guard. Bulebird experts recommend that houses NOT be put on fenceposts because of predation, however; we do offer a predator-resistant fencepost house with internal baffles (a more detailed construction) for $24.