The Lexington Herald-Leader article on The Arboretum's birdhouse event is:
As of July 2013, I've added a 10th step which tells you how to 3D print a smaller version of the "bird house."
Step 1: The Plan
The materials you'll need:
1. The lumber needed depends on the size of the birdhouse. Because the entrance holes (it's actually a 4-family birdhouse) are literally the holes in the letters "b " and "d ," the letter size is tied to the type of bird you want to nest within. In any case, we were able to build everything from scraps I had in my shop, and that might work for you too....
2. A durable finish is needed. We used exterior-grade latex paints for the white and black. The red, yellow, green, and blue colors were actually interior latex wall paint samplers... less than $2 each. I don't really trust any paint to last outside, so the plan all along was to seal everything with 2-3 coats of high-quality clear polyurethane, and that's what we did. You could really use just about any paint as long as you seal it that way.
3. You'll also need a few bolts and screws and a weather-resistant glue. I would have preferred to use biscuits to join the wall panels -- but the plywood we used was too thin for that, so it was blocking, screws, and glue.
I have a fair collection of tools, but you don't need too much for this project. Here are the basics:
1. Saw(s) for cutting the panels and letters. We used a circular saw for the panels and a miter saw and scroll saw for the smaller pieces. The only tricky cut is the angle for the roof (see figure); changing the roof slope so that the two roof pieces meet in a 90-degree angle would eliminate the angled cuts, but add a little height. Hand saws could be used for everything and would have scared my daughter less, but I like power tools. ;-)
2. A drill to make the entry holes and drill holes for a few bolts. If you have a sufficiently large hole cutter, that also can be used to shape the outsides of the "b" and "d" circles; I didn't, so that's what we used the scroll saw for.
3. Sandpaper and/or a power sander. We kept things a bit rustic, but there was still plenty of sanding involved....
Step 2: Make the House
Ok, it's a little more complex than that. If we had used thicker wood, it is hard to beat biscuit joining the corners, but with the thin plywood I had around, there would not have been enough material to hold the biscuits. That's where the pieces across the top come in. These provide enough material to screw into without interfering with where the birds will want to be. Thus, the assembly process was to spread glue on the edges, clamp it together, and then glue and screw the cross pieces.
Step 3: Paint the House
Just give it one coat of black paint for now -- we'll be touching it up later.
Step 4: Make the Roof
After spreading glue along the top ridge where the two pieces of the roof meet, they can be placed on top of the house so that the house acts as a jig to hold them in place while the glue dries.
Let the glue dry and set completely. Then turn the house upside down. Mark the positions for two wooden braces such that both are just inside the front and back walls of the house. Take the roof off the house and glue and/or screw the braces into the positions marked.
After the braces are solidly set, drill a single hole for a bolt to lock the roof onto the house, as shown in the photo.
Step 5: Make the Floor
The floor is just a rectangular piece of wood cut to fit inside the house. It gets attached to the house by placing bolts through some corner braces inside the house. It is easiest to make the floor board, put the house over it, and then attach the corner braces so that they lay flat on top of the floor board. To minimize how much the corner braces intrude on the bird living space, we used just two triangular corner braces.
Once the corner braces are solidly attached to the house, turn the house over and drill holes for bolts in the bottom of the floor going all the way through the corner braces. A couple of bolts dropped into those holes from within the house will firmly anchor the floor using nuts on the bottom.
Step 6: Make the "bird" Parts (two Sets, Actually)
We used 1-by lumber (which is 3/4" thick) to make the letters.
The straight pieces are made by taking a 3/4" by 3/4" square rod and cutting pieces of the appropriate length, with an angled cut for the piece jutting out on the "r".
The circular portions of the "b" and "d" would ideally be cut by using a hole cutter to first cut the outside diameter and then a different diameter hole cutter for the inner diameter. I didn't have a large enough hole cutter for the outside diameters, so we drilled the inside holes and then used a scroll saw to hand-cut the outer diameter.
The dot over the "i" is actually the plug from cutting one of the inner holes. With my hole cutter, that meant the dot actually has a little hole drilled in its center.
Step 7: Put the Letter Parts Together
The circles for the "b" and "d" also need to be cut on one edge to mate with the upright pieces.
Once all the letter parts have been sanded, you'll want to glue the "b", "r", and "d" parts together and paint them. As for the house, just one coat should be enough for now, but you can do more if the color is not even.
Step 8: Put It All Together
Lay the birdhouse on its back and position the "b i r d" letters on the front. The "b" and "d" parts should overhang by 1/4"-3/8" to help give the appearance that the letters go all the way through the birdhouse. Once you have marked the positions, drill holes in the box where the holes in the "b" and "d" will be, then glue the letters in place.
Once the glue has dried, repeat this process on the opposite side. If you wish, you could have the "i" and "r" reversed on the back side so it looks like you're seeing the backs of the front letters -- but nobody sees both front and back at once, so we basically made it with two front sides.
To complete the illusion that the letters go all the way through the birdhouse, there must be a thin board added on each side between the "b" on one side and the "d" on the other. Cut appropriate board to fit, paint it, and glue it in place. Odds are it will not be a perfect fit -- ours wasn't -- which is why you see some wood filler in the photo.
Step 9: Paint & Seal
The roof is taken off and painted white.
Once the colors look good, give everything at least two coats of a high-quality clear polyurethane to seal it and give everything an even gloss. I like the nearly-odorless, water-clean-up, clear polyurethanes, but be warned that although these dry quickly, they are not fully water resistant for some time. I like to give a week or more drying time before exposure to rain, etc.
The tip of the bolt that gets pushed-in to lock the roof in place also gets painted black.
Step 10: A 3D Printed 1/2 Scale Version
To fit a typical printer's build space, the 3D printed version is 1/2 scale. A little math will tell you that 1/2 scale means 1/4 the footprint and 1/8 the volume... so this really large 4-family birdhouse becomes a cozy home for one family. The entry hole also had to be scaled out of proportion to still be viable. However, the design and appearance are pretty much the same as the big wooden unit.
The design and instructions are posted at http://www.thingiverse.com/thing:116905 .