The RSPB have a design for Tawny Owl nest boxes , so i made one three years ago and set it up in a mature Ash tree , Nothing nested in it year one and the next year only a Great tit made use of it.
The design which is basically a tall plywood box with a hole in the top , mimics a natural hole in a tree or snapped tree limb , but being plywood its smooth – giving no grip for the Owl , making getting out difficult , the young leave the nest before they’re fully fledged so only have their talons to climb out. So i took down the box and re sited it on its side, nailing a 3″ x 2″ piece of wood across the base of the entrance – for a perching spot. I also threw a hand full of leaf mould and small sticks in.
The result was this year three eggs were laid and two youngsters left the nest – Result !