How To Make an Owl Box
Making nesting boxes is a really good thing to do. They are easy to make, quick and immensely satisfying.
If you have a small garden there is always room for a nest box for blue tits and a fat ball bird feeder. If you are lucky enough to have a large garden, or know someone who has, there may also be space for an owl box.
DIfferent owls require different types of nesting box. Much though I love the site of a barn owl swooping at dusk, we only have a site suitable for a tawny owl box, so that's what I have shown here. The site is a large branch of a large tree which is far enough from the house for a shy tawny owl to contemplate nesting in. Although barn owls are a more dramatic site, tawny owls make a better sound, the traditional owl hoot (or twit twoo if there are two of them). And they will eat larger mammals such as rats and rabbits, which is a bonus!
Tawny owls like nesting in hollow tree trucks so the idea of the tawny owl box is to mimic this with a ‘chimney box’. It can be made of exterior grade ply (ideally 9-12mm otherwise it gets very heavy) or pine, treated on the outside only with a water based preservative. There should be a few small drainage holes drilled through the base and the bottom of the box filled with an inch of gravel and then an inch of wood chips. Tawny owls do not make their own nests (they are used to having them ready-made in a tree trunk) so if there is no nesting material in a new box it could be a bit bare. Only a little though and of hay or straw.
The precise dimensions of your owl box will depend on the size of the timber you use, but the hole should be 180mm to 230mm across and the box around 800mm long. Ours is strapped to the underside of a branch with wire which is at a 45 degree angle, about 4m off the ground. Fixing it at that height was a challenge though and with hindsight I wish I had had someone to help me!