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.
Avoid bird houses made of metal. Metal houses will become miniature ovens in summer heat, and reflective metals are highly visible to predators. The house can have metal guards or trim over a different material, however, such as a metal cover to fix an entrance hole to the proper size if needed. Healthy Houses: Bird houses can become crowded as nestlings grow, giving diseases and mites greater opportunities to spread to young birds. A safe bird house is one that takes into account the health of the birds.