- Unplaned wooden board ca 15 cm wide and 20-25 mm thick.
- Drill and bit
- Hammer and nails
Saw the board roughly in these dimensions.
Nail the pieces together into a nesting box.
You can let the front be openable at the lower edge so it is easy to clean. It is held in place with an angled nail through a drilled hole in the side. Nail a backplate to the back of the box and then nail it firmly in place on a tree.