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. Weight approx.: 4Kg fixings screws not included for: bird. For: great tit, nuthatch, pied flycatcher.