Don't overcrowd an area with nest boxes. Most cavity_nesting birds defend territories, so don't overcrowd an area with nest boxes for a single species. Usually, nest boxes should be placed 50 feet or more apart. Swallows, however, will tolerate neighbors and will sometimes nest in “apartment” birdhouses. Build your nest box so that it is easily maintained: Construct the birdhouse with a roof or floor that can be easily removed so that you can reach inside to clean it. Maintain your nestboxes: Nest boxes should be cleaned out each spring and disinfected to prevent the spread of avian diseases. Be sure to dry the inside and (if necessary) add fresh, dry sawdust or woodchips.
Snags provide "hawking" perches for flycatchers and resting perches for swallows. Flycatchers perch on a branch, fly out to snatch insects, and then return to the same branch to watch for other insects. Large natural cavities, formed in snags by decay, often provide homes for a variey of mammals including marten, porcupine, bats, bushy_tailed woodrats, northern flying squirrels, and other species. When left to decay and fall over naturally, large hollow snags may provide den sites for larger animals like mink, lynx, red fox, and wolverine. To help provide homes for this wide variety of animals, leave dead trees standing whenever possible, particularly snags larger than 6 inches in diameter and/or any containing woodpecker holes or other cavities.