Field palatability and degradation of a selection of feral cat bait matrices on Auckland Island

Primary poisoning is an important method to ensure the successful eradication of cats (Felis catus) from large islands. Poison bait options for feral cat eradications and landscape-scale control in New Zealand are limited at present. As part of the development of a toxic bait for cats that can be aerially distributed, a nontoxic palatability trial was undertaken on Auckland Island to compare three types of prototype meat-based bait and one currently registered fishmeal polymer pellet for their palatability to feral cats and non-target species. Degradation rates of baits over a range of environmental conditions were also estimated by taking photographs of baits at regular intervals and inferring degradation from visual appearance of baits over time. Fourteen individual cats were sighted on 144 occasions with all individuals consuming at least one bait type. Results show that the three prototype meat baits were significantly more palatable than the fishmeal polymer baits. No native non-target animals were observed consuming any of the baits during the trial. Fishmeal polymer baits degraded at a slower rate than the meat-based matrices. Palatability results for the meat-based matrices are encouraging. Further trials of a toxic meat-based bait will be required to assess efficacy in pursuit of a registered product for wider use.