A natural hollow, because of the influence of the living tree, moderates the internal temperature compared to the external environment – making the hollow cooler in hot weather and warmer in cold weather. Natural hollows also provide a more appropriate humidity for species that utilise such resources. Mature hollow bearing trees need to be retained wherever possible!
A wildlife or nesting box is not a true replacement for natural hollows, in impoverished habitats and urban environments. However, supplementing the available resources by building your own or purchasing a commercially available wildlife box can help provide much-needed nesting and roosting habitat.
Skilled arborists can also create chainsaw-carved hollows in your yard, if you have a suitable large eucalypt on your property. Such hollows can however only be installed in dead trucks or limbs, for safety reasons.
You can discover which local wildlife species (e.g. parrots, possums, bats) depend on hollows or wildlife boxes in your area, through your local museum, natural history organisation/society or Department for Environment. Further information is available on the range of wildlife boxes currently available from fauNature – Nesting Boxes.