Last week Splitrock Environmental teamed up with volunteers from the Lillooet Naturalist Society to build nest boxes for the Western Screech-owl. We’ll be putting the nest boxes up in the Seton River corridor in the late winter. Thanks to all of the volunteers who helped!
The Western Screech-owl is endangered in British Columbia, mostly because of habitat loss. They live in forests along rivers and streams, and rely on big, old trees with cavities in the to build their nests. Without a place to nest, they aren’t able to live in otherwise good habitat. Sadly, their forested habitat is being lost through urban development and people cutting down old trees that seem dangerous or ugly. Building nest boxes is a way to increase the nest availability in an area, and it’s also a fun thing to do to raise awareness of this species. Here are plans for a nest box, if you want to build your own. These plans are adapted from the Audubon Magazine (find the link here).
- Ruler or tape measure;
- power saw;
- power hand drill with attachments
- 1⁄2″ bit;
- 5⁄64″ bit, to pre-drill the screw holes;
- 3″ hole saw;
- Phillips-head screwdriver
- chisel or knife
- 1-foot x 10-foot piece of unpainted wood, 1″ thick. (Remember that when you buy a board of this size at the average lumberyard or home store, the 1-foot width will really be 11 1/4″ and the 1″ thickness will really be about 3/4″.) You’ll end up with leftover wood.
- 24 sheetrock screws (2″ each), coated or galvanized to prevent rusting
- One No. 6 brass wood screw (1 1/2″), with washer
- Two small brass hinges, with screws
- Several small nails, carpenter’s glue, caulking compound
(1) With a pencil, mark off all the cuts you’ll make, starting from one end of the board, according to the dimensions listed below.
1 back (32″ x 7 3/4″)
1 bottom (8 1/2″ x 7 3/4″)
1 front (16 3/4″ x 7 3/4″)
1 side piece (10″ x 35 1/2″). This will be cut in half in step 2.
1 top (12″ x 11 1/4″–the full width of the board)
1 strip (1″ x 11 1/4″).
Cut the piece for the back, the bottom, and the front.
(2) Cut the sides. First cut a piece that’s 10″ x 35 1/2″. Before you make the next cut, be sure you’ve measured 17″ up one side of the board and 18 1/2″ up the other side, and that your cut line connects these two points. You should end up with identical pieces, 18 1/2″ in the back, 17″ in the front, and 10″ from front to back.
(3) Cut the top piece (12″ x 11 1/4″–the full width of the board), then a 1″ full-width strip (1″ x 11 1/4″).
(4) Drill two 1/2″ ventilation holes about 1″ below the top of each side. Drill five 1/2″ drainage holes in the bottom (one in the center, one near each corner).
(5) With the hole saw, drill a 3″ entrance hole. The center of the hole should be 4″ below the top of the front piece. The hole should be centered between the sides.
(6) With the chisel or knife, make horizontal scratches on the inside of the front piece, from the bottom up to the entrance hole (so the young owls can climb out).
(7) Measure about 7″ up from the bottom of the back piece to mark where the bottoms of the sides will go. Screw the side pieces into the edges of the back piece; use three screws for each side. The top of the side pieces should slope toward the front. (Pre-drill all the holes with the 5/64″ bit.)
(8) Screw the bottom of the box in place, setting it about 1/2″ above the bottoms of the side pieces. Use three screws to attach the bottom to each side and to the back.
(9) Screw the front piece in place, aligning it so that its front surface is even with the side pieces. Use three screws to attach the front to each side and to the bottom.
(10) Take the top piece and cut the back end at a slight angle so that it fits flush against the back of the box. (This can be a difficult cut, and might be best made with a small handsaw.) Using the two hinges, attach the top to the back. The top should extend out at least 1″ on both sides of the box and overhang the front by about 2″. Use the brass screw with washer to attach the top of the box to the front; this will hold the top in place but enable you to open the box to clean out the inside.
(11) Finally, take the 1″ x 11 1/4″ strip and glue and nail it to the back of the box, above the hinges (use small nails to avoid splitting the strip). The strip should be low enough to help keep rainwater out of the box but high enough that you can still lift the lid and reach inside. Caulk where this piece meets the back.
(12) Hanging the box
The most important thing to remember when hanging the box: Be careful! Ten feet (or higher) is a long way off the ground, especially if you’re carrying an owl box. If you don’t want to nail or screw the box to the tree, you can attach a cable or light chain to the box through holes drilled in the back (both top and bottom). The cable or chain should be just loose enough to be worked up over the trunk’s irregularities. You might need to tighten the cable or chain when the box is where you want it.