Snags with old woodpecker holes provide homes for swallows, chickadees, nuthatches, bluebirds, owls, and other cavity_nesting birds that are rarely able to excavate their own nest sites. Snags provide ideal hunting perches for Red_tailed and Rough_legged Hawks, Bald Eagles, Hawk Owls, Great_horned Owls, and other raptors. Snags provide "songposts" to a wide variety of birds. Many small birds use songposts sticking above other vegetation to sing (to attract mates and proclaim nesting territory boundaries) and to perch on when looking out for predators and/or other birds.
Train outdoor pets to keep away from bird houses: Behavioral conditioning with a water hose is an effective method that can also be used on squirrels and other wildlife with enough patience and perseverance. Pets should be supervised when outdoors during the nesting season as well, since young birds leave the nest several days before they can fly, making them easy targets for curious pets. Be sure the bird house opening is the right size for the species you wish to attract: If the opening is too large, predators will have easy access to the nest and other bird species may take over. A very large opening may also be dangerous for growing chicks, which could tumble out of the hole. A small hole could cause birds to get stuck, or they won't use the house at all.