Trials of electric fencing for restricting movements of common brushtail possums, Trichosurus vulpecula Kerr

Abstract

The responses of common brushtail possums, Trichosurus vulpecula, to a mesh fence with electrified outrigger wires were examined in a series of trials in an outside enclosure. Possums initially had no hesitation in approaching the fence. Their first contact was usually with the lower hot wire(s). Possums responded to shocks by jumping back, rolling, running away, grooming and head-shaking. Responses depended upon the part of the body contacting the fence. No possums climbed over the electrified fence during a total of 50 trials. Over three or four repeated exposures, eight possums successively took longer to approach the fence and longer to receive the first shock, spent less time in the vicinity of the fence, and received fewer shocks during the first 2 h of the trial. However, over the whole night there was no significant drop in shock frequencies. The addition of a second lower hot wire and an increase in the pulse rate did not prevent possums that had successfully been contained by the fence from breaching the fence when chased towards it repeatedly; 7 of 12 possums were forced over the fence. Possums that had learned to avoid the live fence crossed the fence within 1-7 h after the fence was turned off. Speed and duration of avoidance learning in possums are compared with those in other species. These trials suggest that a combination fence of electrified 'hot wire' and mesh could be useful in reducing contact between possums and farm animals for the control of tuberculosis, reducing possum migration into areas that are free of tuberculosis or of high conservation value, and protecting crops.