Bluebirds prefer nesting boxes that are in open spots with few shrubs and trees. Boxes should be at least 50 feet from areas with lots of trees or brush, which are habitats for house wrens. These birds vie with bluebirds for housing.
Bluebird boxes should also not be set up in areas frequented by house sparrows, because they compete with and sometimes attack bluebirds. Boxes should sit 4 to 6 feet above the ground, facing away from prevailing winds. A box should face a tree or shrub that is no farther away than 100 feet. Immature bluebirds need be able to fly to a landing spot that is above the ground because surface-dwelling predators endanger the youngsters.