The ‘Judas’ Pig Technique: a Method that Could Enhance Control Programmes against Feral Pigs, Sus scrofa

Abstract

The successful ‘Judas’ goat technique has been adapted for use with feral pigs. The ‘Judas’ goat technique involves releasing radio-collared goats into a control area and, after a sufficient period to allow them to join other goats, tracking them down and culling the other individuals associated with them.

Trials with the technique on feral pigs in Namadgi National Park, ACT, indicated that it worked best with sows captured in the same area. Each of these sows established contact with 1–8 other pigs in the area within 1–7 days of release and was located with at least one other pig on 67–100% of occasions. In contrast, sows and boars from outside the study area took longer to come into contact with ‘local’ pigs and associated with them much less frequently.

A subsequent control exercise in Namadgi, using ‘Judas’ pigs to indicate where to lay warfarin baits from a helicopter, resulted in a 75% reduction in the low-density population still present after a larger control exercise two years earlier. Since then, the technique has been used to eradicate a small colony of feral pigs in central Australia and is proving successful for control of feral pigs and other ungulates in other parts of Australia and New Zealand.