Preliminary trial of a water- resistant bait for feral pig control

Feral pigs are regarded as a pest in New Zealand forests because they damage habitats essential for the survival of species such as kiwi and giant land snails. Consequently pigs need to be controlled if these species are to be protected. Most control is done by shooting using dogs to help locate pigs, but this is not possible in areas where there are ground birds or in remote areas. Therefore an alternative option such as poison baiting is required. We investigated the development of a pig bait that would be suitable for burying or using in a bait station, while reducing the likelihood of nontarget species, such as birds, eating the bait. We manufactured a water-resistant pig bait that was eaten by domestic pigs in similar quantities to a non-water-resistant pig bait manufactured by Animal Control Products Ltd. The bait also killed domestic pigs when it contained warfarin. In a preliminary field trial, all feral pigs that visited the baiting site located, dug up, and ate a non-toxic version of the bait when it was buried. When the bait was fed from a bait station, 44% of the pigs present ate the bait. However, this figure would increase if more bait was placed in the bait station or more bait stations were available. We recommend that further trials be undertaken to test the new bait with encapsulated cyanide, which has recently become available. This would offer a more humane and environmentally friendly alternative to warfarin.