Barn Owl (Plan 12)
The barn owl is crow-sized with a white, heart-shaped face. It appears tan from above and white from below and does not have ear tufts. It may be seen roosting in silos and barns during the day, and heard screeching (not hooting) at night. Best habitat is farm-lands. A diet consisting largely of rodents makes this owl an asset to the farmer.
From 3 to II eggs are laid, generally from April through July, but nesting will occur beyond these months if the food supply is adequate.
Changes in the design and construction of barns and silos have resulted in fewer, safe roosting and nesting sites for the barn owl. This, coupled with a loss of farmlands and a loss of best foraging habitat on remaining farmlands, has contributed to the decline of barn owl observations in mid-western states. Insofar as these factors are present in Pennsylvania, there is a potential for a decline in barn owl populations.
Placing barn owl boxes in best habitat can help the barn owl by: 1) providing secure nesting and winter roost sites, and 2) making it easier for biologists and other concerned birders to track the welfare of this otherwise, highly secretive owl.
The "Ohio Box" (Plan 12) is about 40" long (ideally never shorter than
36"), 16" high and 12" wide. It is either five sided (with the open side
against the inside of a barn wall) 
or six sided (hung in a silo). The entrance
to the barnside box (6" to 61/2" on a side) is cut into the barn wall which acts
as the front of the box. For silo boxes, the same-sized entrance should be cut into the
box itself. The box can be constructed from a 6-foot length of l"xl2" pine board
and 1/2" utility grade plywood or it can be made entirely from plywood.
Nail the box together with 7d or 8d box nails. The top should be removable for cleaning the box but secured by hinges and a latch or partially nailed to prevent entrance by raccoons.
When the box is fastened to the inside of the barnwall, the barnside entrance should be about 6" above the floor of the box and about 18' or more from the ground.
Hang the silo box from the top of the climbing-well with 1/2-3/4" rope. The silo should be inactive and have a top opening large enough for access by barn owls.
Keep boxes free of pigeons and their nest litter whenever possible, especially in late winter and early spring. Also, barn owl pellets (regurgitated fur and bones of prey) should be cleaned out of boxes after each nesting.
For barnside boxes, there should be a clear flight-path to the box entranceway which ideally should face open fields (not the property owner's house since young owls can be highly vocal at night).
Nest boxes should be placed in or within a mile of suitable habitat. Best habitats are grasslands, wet meadows, dairy areas and/or numerous woodland-field borders. These habitats often support abundant prey populations. Boxes placed where meadow voles and other similar sized rodents are scarce are least likely to contribute to the stability of barn owl populations.
Barn swallows are a common inhabitant of farmsteads where they frequently nest on the rafters of barns and other outbuildings. Their mud nests are usually stuck onto the sides of rough-sawn rafters. These beautiful birds eat flying insects and are characterized by iridescent bluish-black backs, reddish breasts and deeply forked tails.
Barn swallows also will use the nesting shelf illustrated in (Plan 7). Sometimes barn swallows are a nuisance because they nest over light fixtures in doorways. Then they "defend" their territory against people trying to pass through the doorway. To solve this problem, staple a small piece of clear plastic above the light fixture after knocking down the nest. The plastic will prevent mud from sticking to the wall. The nest should be removed only after the young have fledged. Then place a nesting shelf nearby on the house or garage wall so it is at least 10 or 20 feet from the doorway.