Bob Sheppard's Little Owl nest box design
Traditionally, Little Owls have not occupied nest boxes in great numbers in the UK, making monitoring quite difficult. So, in 1998, my father designed a box that fulfilled all the requirements I felt were necessary to attract them. Crucially, the box had to have a dark nesting chamber and a ducting system to mimic a tunnel. Here is the latest design, as of 2014.
Five boxes can be made for £12 from two sheets of plywood 2438.4mm (8') by 1219.2mm (4') by 12.7mm (0.5") thick. If you are making lots of tree boxes then I would recommend using marine ply, which is far superior, though this increases the cost to £14 per box.
- The sheets for the front, back, base and roof are 381mm (15") by 482.6mm (19") wide.
- The sides, which slot inbetween the roof and base sheets, are 381mm (15") high by 357.2mm (14 1/16") wide.
- When put together, the exterior dimensions of the box end up as 381mm (15") high, 482.6mm (19") wide and 406.4mm (16") deep.
- The door is 165.1mm (6.5") wide and 203.2mm (8") high.
- The entrance hole is 70mm diameter.
- The dimensions of the interior tunnel are not critical so long as they are wider than the 70mm diameter entrance hole. In the example shown, the interior dimensions of the tunnel are 101.6mm (4") by 101.6mm (4").
- The gap at the end of the tunnel is 88.9mm (3.5") wide. This keeps the chamber nice and dark, which is the key to successful occupation.
- 40 stainless steel screws, 40mm long, are used to hold the box together.
- A ring of Tippex is put around the entrance to help determine occupancy. The ring becomes discoloured when the box gets used.
- A thick layer of wood chips should be placed in the bottom for the birds to nest on.