Bird Houses are designed for birds that normally use natural cavities or create their own in trees for nesting and to raise their young. The most common birds to use houses are bluebirds, swallows, chickadees, tufted titmice, nuthatches, wrens and house sparrows.
The size of the opening can somewhat determine what kind of bird you attract. For instance, a 1" hole will allow only a wren while a 1.5" hole will allow any bird the size of a bluebird or smaller to use it. (The 1.5" hole will deter European Starlings from using the box)
Houses can be attached to trees, fenceposts, poles or hung from branches.