Carolina Raptor Center - Owl Box Plans

Barn Owl Nest Box		Barred Owl Nest Box

click to open printable version of plans		click to open printable version of plans
For the "do-it-yourselfer," the Barn Owl box can be built from a single sheet of 3/4" exterior grade plywood, treated with a preservative. Sections are secured with 2-1/2" sheetrock screws. A hinged and latchable door (16" high x 18" wide) provides access to the box for cleaning after the owls have left. The entrance hole should be 10" x 8" and has a door hinged at the bottom. A 2 x 2 perch extends across the box just inside the entrance hole.		We have modified our Barn Owl Box plan for Barred Owls. Because Barred Owls only have 1-3 young, as a rule, they don't need as big a box as the Barn Owls, which can have as many as 7 or 8 young in a brood! Although we have made our first several boxes out of 3/4" exterior grade plywood, the boxes can probably be made of 1/2" plywood. The smaller and lighter boxes will be more maneuverable and permit us to put them higher up in trees, which the Barred Owls probably prefer.
Boxes can be mounted on barns, trees in open fields, or free standing on either two treated 16’ 4 x 4s, or a single 16' 4 x 6, sunk 30" in the ground. The CRC will provide, at the cost of materials ($100), boxes for those who can't build their own. Additional donations to support additional boxes are tax deductible and respectfully requested.

Constructing Your Nest Box

»For the Barn Owl boxes, be careful when cutting the plywood that the lengthwise cut is exactly in the middle-the two pieces don't need to be exactly 24", but should be the same width.
»For either kind of box, when your pieces are cut, they should be treated with a preservative before assembly, especially the newly sawn edges.
»When assembling the pieces, it helps to nail them together with 1-1/2" nails before securing them with the sheetrock screws.
»Once the box is nailed together, predrill holes for the sheetrock screws with a 1/8" bit. Space screws about 5" apart. (If you're using an electric drill as a screwdriver, the sheetrock screws can be screwed in without predrilling.)
»Make sure no screws penetrate the inside of the box. The sharp points could injure the young owls.
»The two door holes can be cut with a circular saw after the box is assembled. Because the saw cuts at an angle, if you stop cutting when the circular saw blade cuts just meet on the outside of the box, the doors will still be connected to the surrounding wood. The hinges can now be applied, after which the cuts at the four corners can be finished with a keyhole or saber saw.
»Once the box is assembled, it should get another full coat of preservative--inside and out. A heavy duty deck stain is ideal.
»Drill a dozen 1/2" drainage holes in the floor of the box.
»For Barn Owl boxes, use a hasp or throw bolt on both doors that can be securely fastened.

Mounting the Box on a Pole

»Barn Owls need to hunt in open country, so boxes should be placed at the edges of fields or on barns with lots of open space around them.
»Barred Owls prefer forested habitat, particularly near streams or wetlands, although they seem to be doing well in forested suburban situations. Their boxes should be about 20' or higher up on a tree.
»The box should be bolted to the pole (or poles) with three 5-1/2" bolts drilled all the way through the pole prior to sinking the pole in the ground. Have the threaded ends to the bolts on the outside of the box so they don't protrude into the box itself. This will reduce the chance that the young might be injured when researchers reach into the box.
»When the pole is ready, one or two 30" holes (depending on whether you're mounting the box on a single 4x6 or two 4x4s) should be dug with post-hole diggers. To facilitate erecting the pole, dig a trench at a 45o angle to about half-way down the hole. Place a 2 x 4 in the back of the hole(s) on the side opposite the trench. Lay the nest-box pole over the trench with its bottom up against the 2 x 4. As you raise the box, the pole will slide down the 2 x 4.
»Level the pole and pack the soil firmly around it. Keep tamping the soil firmly as you fill the holes. It is most important to pack the soil well at the bottom of the hole as you begin to fill it.
»To protect the nest box from raccoons and other predators, nail a 3' wide strip of metal flashing tightly around the base of the pole, starting about 3' off the ground.
»When the box is finally installed, place a couple of inches of pine straw or some other mulch (not cedar chips) in the bottom of the box.

Mounting the Box on a Tree or Building:

»This procedure can be very dangerous because the box must be suspended or supported in place before it it bolted to the tree or building. We secure a pulley above the spot where the box will be mounted and pull it into place from below. Once it is at the desired level, we tie it off and climb ladders beside the box to secure it to the tree. REMEMBER: The boxes are very heavy so make sure no one is beneath the box as you are fastening it to its support structure! Be sure the rope you use to pull the box up is strong enough and tie good knots!
»Bolt two 12 x 1-1/8" zinc-plated mending braces (Home Depot/Lowes) to the back of the box with half the braces extending above the box. (Make sure the threaded ends of the bolts are on the outside of the box).
»Now use hex-head lag screws to fasten the protruding parts of the braces to the tree or side of the building. Alternatively, you can pre-drill holes in the back of the box and then use lag screws (with big washers!) to fasten the box directly to its support (tree or building). If mounting the box on a tree, pre-drilling 8 - 10 holes will increase the likelihood that 5 or 6 holes will match up with a flattish surface of the tree. Having lag screws of various lengths (from 3 to 6") will also ensure that you can get a good purchase in the tree, should the tree surface be irregular and not match up well with the back of the box. You'll need a hammer to get the lag screws started and a ratchet wrench to set the lag screws
»Boxes mounted inside a barn do not need a roof piece!
»A metal or wooden angle brace may be needed from the bottom of the box to the wall beneath it (although we haven't found this to be the case).