Aspects of the Ecology of Feral Pigs (Sus scrofa) in the Murchison Area, New Zealand

Seven feral pigs (Sus scrofa), radio-tracked in relatively undisturbed rough pasture and forest near Murchison, New Zealand, for periods of 18-186 days, occupied home ranges of 28-209 ha. The immature pigs were significantly more active and had significantly larger home ranges than the adults, particularly adult females. The pigs were mainly nocturnal but they varied individually. The frequency of grazing and the rooting up of pasture and bracken (Pteridium esculentum) varied seasonally. Some of the pigs preferred pasture and bracken in their home ranges while others preferred mixed beech (Nothofagus spp.) forest. The number of pigs and their use of habitat were probably related to the seasonal availability and quality of food and shelter. Farrowing occurs throughout the year but Peaks during spring. Litter sizes ranged from 1-9. Density was roughly 12-43 pigs per km² compared with 3-8 per km² in a nearby, more heavily hunted area.