Nesting Box Spacers – small spacing rings which fit over the bolts that attach the nesting boxes to a tree. They serve two purposes 1) simplify the installation process on difficult trees; 2) perhaps more importantly allows the tree room to grow, while minimising the impact on either the tree or the box.
Spacers are highly recommended for the installation of any wildlife/nesting boxes which are to be attached to a tree. Spacers are not required if a box is to be installed non-growing sufrace (e.g. building, pole or dead tree). For most boxes two Spacers are required; while three Spaces are required for Large Parrot Boxes.