Gather the Wood
The best wood to use for your birdhouse is cedar or redwood, because both stand up to Portland’s weather quite well, even when left natural. Plywood or oak will also work, but may not be as long-lasting and weather-resistant. You’ll only need to buy two boards: a four-foot-long one-by-six and a 10 ½-foot-long one-by-10. You can cut each of the pieces you need from these two pieces of lumber. Avoid any pressure treated woods because of the toxic compounds they contain, which can be harmful to birds. You can find pre-cut boards of the right dimensions at Home Depot (multiple locations, homedepot.com) or Lowe’s (multiple locations, lowes.com), but for a birdhouse with a little more character, take some time to scavenge around local reuse warehouses like the ReBuilding Center (3625 N Mississippi Ave, rebuildingcenter.org) for recycled boards or panels. If you do opt for pre-painted boards, make sure one side is left natural—the inside of your birdhouse should not be painted. The ReBuilding Center also periodically offers birdhouse building workshops, so check their website often for the latest schedule.
Make your Cuts
Your 4-foot-long board will become the walls and floor of your birdhouse. Remembering the wise old adage, “Measure twice, cut once,” it’s a good idea to trace each cut before you make it, being as methodical as you can.
Start with the four-inch floor piece and work your way through cuts for the walls and, finally, the back slab (the least critical dimension), remeasuring after each cut and labeling your pieces as you go. For the floor, simply measure four inches from the end of the board and cut straight across. Then make a small diagonal cut at each corner of the floor piece (basically cutting the corners off) for easy drainage and ventilation.
For the walls, you’ll want to measure two different lengths from the freshly cut end: 10 inches on the left and 9 inches on the right. Draw a diagonal line connecting the two points and make the cut. This will give you two sloped sidewalls.
The next piece will become your birdhouse’s front face. It’s a good idea to drill your entry hole before you make the cut, using the remainder of the board as leverage on a table. This entry hole will be critical to the success of your birdhouse; its relatively small 1 ½-inch diameter precludes the entrance of the Western Bluebird’s most feared predator: the European Starling. Both European Starlings and House Sparrows, introduced from England in the ‘40s, compete with bluebirds for nesting sites—the Starlings can be eliminated with the small entry hole. So to protect your timid bluebirds, it is very important to use a 1 ½-inch spade bit in your drill for the entry hole, which should be about six inches from the bottom of your birdhouse’s façade.
The remainder of the board four-foot board will become the back of your birdhouse. Keep in mind that allowing the back to extend both above and below the main box body will make mounting your birdhouse very simple.
If you buy a board for the roof that is exactly 10 ½-inches long, you won’t have to make any cuts.