Our woodstone® range of nest boxes have been designed and developed as part of our professional vivara pro range. Unlike a traditional wooden nest box, these boxes will not rot away or deteriorate. Every woodstone® nest box from cj wildlife is guaranteed for 10 years. Constructed from a mix of concrete and wood fibres, woodstone® nest boxes safeguard against attacks from predators including woodpeckers, cats and squirrels. The material insulates the nest which creates a more consistent internal temperature than an ordinary wooden box. This is especially important during the breeding season and ensures that young birds have a greater chance of survival. We recommend using aluminium nails to hang due to the weight of the nest box and to limit any damage caused to trees. These 32mm hole nest boxes will be used by house sparrows, redstarts, tree sparrows and great tits. The oval hole is preferred by house sparrows and redstart over traditional round hole nest boxes and house sparrows in