Step 1: Materials

Assemble all your materials:

Measuring tape and pencil
Wood glue
Hammer
1 1/4" nails
Wood (I used scraps from a free pallet and a free piece of 3/8" plywood from Home Depot)
Miter saw
Drill with 1 1/4" hole drill bit
Clamps
Screwdriver
2 screws

Step 2: Cutting

I used the 1" thick pallet board for the sides. The rest of the pieces were cut from 3/8" plywood at these dimensions:

Front - 7 7/8" x 5" with a 15 degree angle on the top
Back - 14" x 5"
Sides - 9" (highest point) x 4". Cut a 15 degree angle on top of this to create the roof angle. You'll need two of these.
Bottom - 5" x 4 3/8"
Top - 6" x 6" with a 15 degree angle cut vertically to create a flush finish on the back.

Don't forget to cut the hole into the front board. Place it approximately 5 1/2" up from the bottom and in the center. Make the hole 1 1/4".

Step 3: Assemble

Now we can begin assembling

1) take the two side boards and the back board. Place the side boards 2" up from the bottom of the back board. This allows for a 3" gap at the top. Using the wood glue and 6 nails, piece it together.
2) Attach the front board in the same way using 4 nails and the wood glue
3) Clamp what you have so far. How long you let it sit depends on what type of glue you use. I had quick drying 10 minute glue which worked well.
4) Remove the clamps and attach the top board with glue and 4 nails. Make sure the 15 degree angle is in the right spot (see picture)
5) Screw the bottom piece into place. This allows for easy cleaning of old nests!
6) Now clamp the top