Evaluation of Conditioned Taste Aversion as a Method to Reduce Predation of Wildlife Eggs by Feral Pig (Sus scrofa)

Ricardo F Tapilatu, Emma Guyris, Jim Mitchell


Feral pigs are introduced predators to Australia and New Guinea. Predation by feral pigs on eggs and hatchlings of nationally protected sea turtles and other wildlife can cause significant mortality. Several control techniques are available to minimize pig predation but available techniques are expensive and of limited success. A potential method is to teach feral pigs to avoid predating eggs by using Conditioned Taste Aversion (CTA). In this study, it was hypothesized that if eggs were treated with deterrent chemicals, feral pigs would develop an aversion to the eggs, and would stop predating them. Sixteen feral pigs were presented with eggs treated with the distasteful chemicals: TBZ and LiCl for 5 consecutive days following a pre-treatment phase during which they were fed untreated eggs. The percentage of eggs predated during the treatment phase was lower than in the pre-treatment phase, though in most cases this difference was not statistically significant. Most eggs predated during the treatment phase were only partly eaten, suggesting that pigs were taste-testing. In addition, pigs consumed similar proportion of untreated eggs and control eggs during the pre-treatment and post-treatment phases.

Thus, taste aversion was not established. In a second experiment, external scent cues were applied to the eggshells. It was hypothesized that the pigs would only consume untreated eggs, and leaves the treated-scented eggs untouched. A new group of 16 feral pigs were presented with scented eggs treated with TBZ and LiCl for 10 consecutive days. The pigs still predated by partly consuming the scented-treated eggs. Similar percentages of untreated and scented-control eggs were predated during the pre-treatment and post-treatment phases. This study failed to provide support for CTA as an effective method of controlling feral pig predation of wildlife eggs.


Feral pigs; Conditioned Taste Aversion, TBZ, LiCl, pre-treatment, treatment, post-treatment, untreated, predated

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