Effect of twin-lead type electric fence for deterring scansorial animals

Abstract

Electric fences are usually effective in deterring terrestrial wild animals. However, they can prove inefficient in case of scansorial animals such as martens and raccoons, which can touch the electric fence without being grounded, thus not experiencing the electric shock. To overcome this limitation, we developed a twin-lead type electric wire fence comprising two parallel conductor wires spaced by a polyethylene ribbon containing two wire lines: one connected to the power source and the other connected to the earth. We then investigated whether the twin-lead type electric wire fence could effectively deter scansorial animals using two species: the Japanese marten and raccoon. A feeder was installed on the top of a pole at a height of 1.5 m above the ground. Three test plots were set up: (1) the twin-lead wire wound around the pole: an electric wire fence plot (“EF plot”), (2) a commercially available barbed iron plate plot (“BP plot”), and (3) no countermeasures against scansorial animals: control, unfenced plot (“CT plot”). The behavior of the scansorial animals attracted to each feeder was recorded using remote video cameras. Variable voltage appliances were attached to the electric fence and the deterring effect of scansorial animals was compared among test plots. The experiment comprised six experimental stages, which differed by the use of electric voltage in the twin-lead fence. We observed that the Japanese marten experienced an electrical shock from the fence at a voltage of approximately 2 kV and avoided the EF plot in further experimental stages with higher voltages. The raccoon began experiencing an electric shock at a voltage of approximately 0.5 kV and avoided EF plots in experimental stages at > 2.8 kV voltages. Conversely, the effects of the barbed iron plate could not be confirmed against both the species. These results show that the twin-lead type electric wire fence can effectively deter scansorial animals from climbing, when energized with voltages > 2.8 kV.