Does temperature drive tree hollow selection in an arboreal mammal?

We investigated whether the inland sugar glider (Petaurus notatus) showed a seasonal preference for chainsaw-carved tree hollows over nest boxes. We installed chainsaw hollows (CHs) and equivalent volume nest boxes (NBs) in pairs across eight sites in southern Australia. Twenty-one pairs of artificial hollows were surveyed on 17 occasions over a 3.4-year period. Dataloggers confirmed that in peak summer, temperatures were lower and fluctuated less within the CHs than within the NBs. Sugar gliders used both types of hollow, but detection in CHs was approximately twice as high as that in NBs. We found no evidence that CH use increased as ambient temperature increased or was higher in summer. Use of both types was greater in Year 3 than in Years 1 and 2. Although there are legitimate concerns around the fitness consequences of high and variable temperatures for mammals using nest boxes, our study does not support a discontinuation of nest box instalment. Habitat restoration for tree hollow-dependent wildlife is likely to be more effective if all options are available. Nest boxes have the advantage that they can be installed on small-diameter trees.