The influence of snow cover on home range and activity of the bush-rat (Rattus fuscipes) and the dusky antechinus (Antechinus swainsonii)

Abstract

Radio-telemetry was used to investigate changes in home-range sizes and activity patterns of Rattus fuscipes and Antechinus swainsonii in a subalpine heathland at Perisher Creek, Kosciuszko National Park, southern New South Wales, in response to the accumulation of snow during the winter. We estimated home-range area for each animal during the autumn and winter using two methods, minimum convex polygon and 95% and 50% utilisation contours using the kernel method. With both methods, the home ranges of R. fuscipes and A. swainsonii were significantly smaller (P < 0.001) during the winter than in the autumn. In winter, both species were restricted to areas of dense wet heath close to the main drainage line. R. fuscipes showed signs of social interaction during both seasons, as indicated by location fixes and gnawing damage to radio-collars, in contrast to A. swainsonii, which appeared to remain solitary. In winter, R. fuscipes apparently nested at a single location, whereas during autumn it appeared to use several nest sites. There was no significant change in daily activity patterns between autumn and winter in either species. R. fuscipes remained primarily nocturnal during both prenival and nival periods whereas A. swainsonii continued to be active throughout the diel cycle, although there was a slight shift in its peak activity time from around sunset in autumn to early morning in winter.