Build a better birdhouse

Sunset, March, 1999 by Peter O. Whiteley

Start with the basic wood shell, then embellish

This shed-roof birdhouse, sized for small birds such as wrens, chickadees, and bluebirds, incorporates bird-friendly characteristics: the deep overhang, perchless entry, openings for air circulation, and easy access to the interior for cleaning. It's built from rough-sawn redwood, but you can substitute other woods. The birdhouse is based on a design from Howard Rathlesberger, a member of the California Bluebird Recovery Program: CBRP, 2021 Ptarmigan Dr., Suite 1, Walnut Creek, CA 94595.

TIME: About an hour

COST: About $5

MATERIALS

* 4 feet of 1-by-6 redwood fencing

* 25 inches of 1-by-8 fencing

* 15 11/2-inch woodscrews

* Two eightpenny nails

You don't have to be a woodworking whiz to build the shell: it requires only straight cuts that you can make with a handsaw, saber saw, circular saw, or table saw. You'll also need an electric drill, drill bits, a 1 1/4-inch paddle bit, a tape measure, a straight-edged ruler or combination square, and a pencil.

DIRECTIONS

The rough-sawn lumber we used was 7/8 inch thick. The width was 5 7/8 inches for the 1-by-6 and 7 7/8 inches for the 1-by-8. Check the dimensions of your lumber, since it could affect the size of the door and floor pieces.

1. Cut boards to the sizes shown in plan at right. Trim corners off floor piece (for ventilation).

2. Stand the side pieces on their 12-inch-long edges, overlay the back flush to the outside and bottom edges of the sides, and secure it with three woodscrews per side.

Note: The tips of the angled sides should extend 1/4 inch above the back to create an air-circulation gap when the roof is added.

3. Position the floor piece between the sides 2 inches from the bottom, and secure to the sides and back, using one screw for each board.

4. On each side piece, mark a point that is 1 inch up from the bottom and 3/8 inch in from the front edge. Drill a 1/8-inch hole through each side at this point, insert the front piece between them, and run a screw through each hole into one edge of the front. Check that the front pivots easily on the screws; it will be the door.

5. Position the top so it overhangs the back about 1/2 inch and the sides evenly. Check that the door clears the overhanging roof Remove the door and roof.

6. Center and drill a 1 1/4-inch-diameter hole in the door so the center of the hole is 2 inches from the top of the door. On the inside face of the door, cut 1/8-inch-deep horizontal grooves at 1/2-inch intervals between the hole and the floor piece (see photo at right). These will serve as a climbing ladder for young birds.

7. Cut a similar shallow groove 1/4 inch from the front on the underside of the roof piece. (It serves as a drip edge.) Replace the door and secure roof with four screws.

8. Finally, drill a hole for an eightpenny nail at a downward angle through each side and into the edge of the door. The holes should be slightly wider than the nails, so the nails can be removed easily to open the door for nest cleaning.

Embellish as you see fit. Secure the house to the trunk of a tree or a post or, adding eye screws to the roof, hang it from branches.

Birdhouse design tips

Not all birds will nest in birdhouses, but those that do aren't very fussy about aesthetics. What they do care about is safety and proper size. Here are some rules of thumb - er, wing.

* Use the appropriate configuration and the right size of hole for the particular species you wish to attract.

* No perches allowed.

* Make birdhouses openable for periodic cleaning or monitoring.

* Provide air circulation and drainage.

* Build with wood - for its insulation qualities and ease of construction.

* Select natural or muted colors - bright colors can attract predators. Don't paint interiors of houses.

* Add a textured surface on the interior wall below the entry to allow hatchlings to climb to the hole.

* Angle the roof and extend it well beyond the entry, both for drainage and to discourage predators.