Erecting nest boxes not only increases the available breeding sites for resident birds, but may attract birds into areas where they have not bred before. It may take a while for the box to be discovered and used, but not always. Two years ago in early June I installed a box in an unused silo where Barn Owls had been roosting. Three weeks later an owl was in the box, incubating eggs. She must have been waiting for me to show up with her nest.
Two designs work well for Barn Owls. The open tray type is the easiest and least expensive to construct. This type should be used inside a barn. silo or other building where a roof or covering already exists. Place the box high in the structure where it will be inaccessible to house cats, raccoons, or too much human disturbance. The box can be nailed fast or hung with rope, wire or brackets.
The closed box type can be used in a topless silo, attached to the outside of an existing structure, erected on a pole or placed in a tree. When erecting on poles or trees remember to choose open areas, fields, meadows, etc. and face the entrance hole south.