Build a Winter Bird Roost Box in 3 Hours for $30
A roost box saves birds only if the entrance sits near the bottom and the perch pegs are staggered, because warm air rises and huddled birds need to trap it.
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Songbirds can lose a quarter of their body weight on a single freezing night, and a regular nest box often does them little good in December. The difference between a roost box that saves lives and one that becomes a cold wooden freezer comes down to the entrance hole position. Heat rises, so a hole drilled near the top lets precious warmth escape, while a hole near the floor traps rising body heat inside, where a dozen huddled birds can share it. Staggered interior perches let them stack without anyone getting soaked by droppings. This cedar build takes about 3 hours for $30, needs only basic tools, and is a great early-December project, since birds start hunting for shelter right as hard freezes begin.
What You'll Need
- Materials (~$30 total):
- One 1x8 untreated cedar board, 6 feet long (~$14)
- One 1x2 cedar furring strip, 4 feet long (~$4)
- Three 3/8-inch hardwood dowels, 12 inches long (~$3)
- 1 1/4-inch exterior deck screws, box of 20 (~$5)
- One 1/4-inch-thick scrap or small hinge-free cedar shingle for the roof overhang (~$2)
- Small stainless-steel hook-and-eye latch is not needed; use two extra deck screws for the cleanout door (~$2)
- Tools:
- Handsaw or circular saw
- Drill with 1/8-inch bit, 3/8-inch bit, and 1 1/2-inch spade or Forstner bit
- Tape measure and pencil
- Sandpaper, 80 grit
- Safety glasses
How to Do It
- Cut the 1x8 into one 12-inch back, one 10-inch front, two 10-inch sides, one 5 1/2-inch floor, and one 8-inch roof. Untreated cedar resists rot and is safe for birds, unlike pressure-treated wood with chemical preservatives.
- Angle the top edges of both sides by marking a slope from 10 inches down to 8 inches and cutting along it. This slope sheds rain and snow so the roof does not pool water that would freeze.
- Drill a 1 1/2-inch entrance hole in the front panel, centered 1 inch up from the bottom edge. A low hole traps warm air like an upside-down cup, which is the single feature that makes this a roost and not a nest box.
- Mark the inside of both side panels for three dowel perches, staggered at 3, 5, and 7 inches up. Drill 3/8-inch holes halfway through each side, then push the dowels in. Staggering keeps birds from perching directly above one another.
- Drill four 1/4-inch drainage holes in the floor and pre-drill all screw locations with the 1/8-inch bit. Condensation builds up inside in winter, and pre-drilling prevents the cedar from splitting in the cold.
- Assemble the sides between the front and back, with the floor set 1/4 inch up inside the walls. Use deck screws, leaving the front panel attached by just two screws at the top, so you can unscrew it later for cleaning.
- Attach the roof so it overhangs the front by 2 inches, then sand every rough edge. The overhang keeps sleet off the entrance and keeps the interior dry, which matters because damp feathers lose their insulation.
- Mount the box 8 to 10 feet up a tree or post, facing southeast to catch morning sun, and tilt it slightly forward. Add a handful of pine shavings inside. Check that it is stable before you leave.
Wildlife habitat specialists at Audubon-style bird conservation programs recommend leaving the box unpainted and unstained, and cleaning out old droppings once in late winter. Make the interior walls slightly rough by scoring them with a screw tip in horizontal lines, which gives tiny claws something to grip when birds cling.
