Time budget of the squirrel glider (Petaurus norfolcensis) in subtropical Australia

Abstract

Exudivorous mammals exploit food items of high quality and high rates of renewal, offset by wide dispersion and variable availability. How this influences foraging effort and size-related foraging efficiency remains poorly described. We examined the time budget of 5–6 male and 5–6 female squirrel gliders (Petaurus norfolcensis) during 6–8 nights in each of three seasons that were stratified by moon phase. Radio-collared gliders were observed during a series of 1-h focal observations from dusk until dawn. Feeding dominated the time budget, accounting for 78% of observation time, or 85% of time when combined with behaviours associated with foraging. Females appear to maximise feeding rates before entering the energetically demanding phase of late lactation. Little time was spent resting while outside the den. Longer nights and the full moon were associated with later emergence and earlier retirement times. Animals re-entered their tree-hollow dens during the night, representing 2% of activity in late spring, 18% in winter and 9% in autumn (10% overall). This behaviour may relate to predation risk and lactation demands. We reviewed the percentage of the time budget that petaurid gliders devoted to feeding and found no clear relationship with body size.