The WoodStone® Build-in Invisible Swift Box is constructed from certified sustainable WoodStone®. The box is designed to be incorporated into the wall and then covered with building materials that form the building's outer skin. An entrance hole of at least three centimetres tall and at least six centimetres should be left, by leaving a slightly larger entrance, around 3.5cm will encourage other species such as house sparrows to occupy the nest. Leaving most of the entrance exposed and siting the box below five metres will encourage robins, wagtails and black redstarts to occupy the nest box. For swifts, the nest box should be sited at least five metres high and not south-facing.
Swifts usually breed in social colonies, so it is recommended to site multiple boxes together, but they must be at least 40 cm apart.
Warranty: 10-year guarantee.