Aspects of the ecology of common wombats (Vombatus ursinus) at high density on pastoral land in Victoria

Abstract

Free-living common wombats (Vombatus ursinus) living at high densities on pastoral land (1.9 wombats ha^–1) had most of their burrows (83%) confined to a 20-m-wide strip of remnant riparian vegetation adjacent to pasture (24 burrows ha^–1). The ratio of wombats to 'active' burrows (being used by wombats) was 1.0. Wombats shared burrows extensively, with a mean of 3.1 ± 0.3 (s.e.), range 2–9 wombats using each burrow (n = 37). The majority (70%) of occupied burrows contained several wombats independent of age, sex and stage of reproduction. On average, wombats used the same burrow for 3.8 consecutive nights before changing to another. Home ranges of wombats overlapped completely. Adult males had larger home ranges than females with young (7.3 ± 0.6, 6.1–8.3 ha, n = 3 versus 3.8 ± 0.5, 2.4–5.0 ha, n = 4, respectively). Distances travelled and the area used each night by wombats decreased in late winter and spring, when food was more abundant. Breeding occurred throughout the year but there was a cluster of births in summer. Lactation was associated with weight loss in females of several kilograms. Usually larger (30 kg) males that shared burrows or used burrows near (<300 m) to the burrows used by a female sired her young; however, occasionally wombats that used widely separated burrows (>700 m) bred. Adult males had a greater head length to weight ratio than adult females. Adult males generally emerged from their burrows shortly after dusk and 30 min before adult females. Ectoparasites such as ticks, mites, fleas and lice were common but the mite Sarcoptes scabiei was not found nor were there signs of sarcoptic mange in the population.