Tree Trunk Birdhouse - two sizes

This is my attempt at making a birdhouse that birds will actually use and that meets standards for a bird nesting location. At full size the opening is 1 ¾ inches or 42mm suitable for Blue birds and Finches. I included drainage holes at the bottom, and the lid has small holes on the sides to secure it with a screw. 

I've also included a smaller set one with the opening  1 ¼ inches. The mounting holes are the same size as the larger version so you can use the same screws. I used deck screws for mounting. 

The mounting options include recessed keyholes on the house itself (1cm deep), a tree mount the house can slide onto, and I also included 4 holes in the house to mount with wire, zip ties, or bungie cords.