BYOB (Build Your Own Birdhouse) for about $1.50

Seriously though folks, it's really easy, I could have made 2 dozen birdhouses in the time it took to lay out this post. There's 11 cuts, 3 holes to drill and a few nails. If you want a couple dozen, cut out all the pieces at once by clamping a jig in your miter saw.
Here's what you need to build the simple one size fits many house. About 3 feet of 1x6 (72 cents), 2.5 feet of 1x4 (40 cents). Rough lumber is best. The sides are cut on a 22.5 degree angle to give the slope to the roof. You can choose any angle, I like the this look and it is a click stop on the miter saw. The roof is then beveled on the same angle to fit flat at the back. The top of the front and back are also beveled to 22.5 degrees. I use the sides to mark the cuts for the front and back. The 1.5 inch hole is about 8 inches off the floor.

With rough lumber each board is a slightly different size, to avoid having to rip each piece to size, try to make the front, back and floor out of the same board, this way all three should be the same width. If the back or floor is narrower than the front, it will be hard to open.

The floor should be about 4x4 inches but may have to be sized differently, depending on the exact width of the side pieces.

Nail the sides to the back, keeping it flush at the top. Then nail the floor, but dry fit the front first to make sure the door will close tight.(middle above) It's a lot easier to return to the saw and trim a bit off the floor before you nail things together.

Put the front in place, here I leave it down from the top a bit, this provides a vent hole and the part that protrudes down past the floor will give you something to get a hold of to open the door. Pre drill two 1/8 inch holes through the sides into the front just above the entrance hole, attach with 2 inch nails, these will act as pins that the door will hinge on, try to make these the same on both sides so the door will open easy. (you don't need to be exact, just close)

Put the roof last, I use (over use) PL premium construction adhesive, this really holds the roof on well as it tends to dry on top and curl, pulling out the nails. It also fills in any gaps along the top. (PL Premium is odorless, so you won't get a buzz on while using the saws, and it has a long open time, you could apply the glue to a dozen houses at once, then nail all the roofs on. The PL 200 or PL 400 will get you high and it starts to tack up in just minutes.)

Last, to hold the door shut, I use a deck screw. I used to use a button, but they break and the door hangs ajar, kids tend to want to look in, they don't add anything structurally and mostly the screw is a lot easier. If you need to you can use it to help open the door.

Place these on posts between 4 and 6 feet high, (trees aren't as good as squirrels will use them,) and watch the Tree Swallows, Chickadees, Bluebirds, and maybe Nuthatch, House Finch, Downy Woodpecker. If you live somewhere other than Atlantic Canada, House Wren, Tufted Titmouse, Prothonotary Warbler and maybe even more will partake. Good luck!

Written by Dwayne Biggar at The Bird Garden