Place the owl house on its base, front facing you. Measure 60mm in from the side, about 130mm from the base. Make a mark. From that mark draw a box 170mm up and 120mm wide, but with a gently rounded top. This will be the owl’s front door. Using the 10mm drill bit, drill a hole just inside each corner of this doorway. Using these holes as starting points, cut out the doorway using the jigsaw. Lastly, screw the 200mm landing perch flush with the bottom of the doorway, to give the owls some purchase when landing and taking off.