Johnston, M., O’Donoghue, M., Holdsworth, M., Robinson, S., Herrod, A., Eklom, K., Gigliotti, F. Bould, L. & Little, N. (2013). Field assessment of the Curiosity® bait for managing feral cats in the Pilbara. Arthur Rylah Institute for Environmental Research Technical Report Series, (245).
Management of feral cat populations over large areas in Australia is currently limited by lack of a cost-effective control techniques. Existing techniques, including trapping, shooting and fencing are subject to limitations associated with significant input cost when used in broad areas. The distribution of poison baits can provide a lower cost alternative but must necessarily address the hazard that the baits may present to non-target species as baits intended for feral cats must be surface-laid. A bait, known as Eradicat®, has been developed for application in areas where native wildlife have a high tolerance to the poison (sodium fluoroacetate) used in that product. This bait is not suitable for use in other areas, such as eastern Australia, where this tolerance does not exist due to potential for consumption of the bait by wildlife species.
The Australian Government has funded the development of an alternative poison bait product that is a based on Eradicat. This bait, known as Curiosity®, exploits differences in feeding behaviour between feral cats and non-target species by presenting the toxicant, para-aminopropiophenone (PAPP), in an encapsulated pellet.
Curiosity baits were aerially distributed over a 268 km2 area within Karijini National Park, Western Australia in August 2012. This trial was part of a series of field trials conducted across Australia to assess the efficacy of this bait product and will contribute to the data submitted for product registration purposes.
Monitoring of the bait efficacy program was undertaken by assessing site occupancy of feral cats prior to and following baiting using automated cameras. Additionally, the survival of eight cats that had been trapped and fitted with a GPS datalogger / VHF telemetry collar prior to baiting was monitored. The study included replicated counts of birds prior to and following to determine whether the Curiosity® baits led to a decrease in populations of non-target species. Impacts on reptile populations were expected to be mitigated given that the application of baits was timed for winter when these species were minimally active.
An analysis of site occupancy data showed that there was no significant reduction in the feral cat population after baiting. None of the collared cats died as a result of bait consumption, despite numerous opportunities to encounter the bait as indicated by the GPS datalogged locations.
Corvids and dingoes were photographed removing and consuming baits from a limited number of sites. However, as these individuals were not ‘marked’ or otherwise identifiable, it was not possible to monitor their fate throughout the study. Counts of non-target bird species did not show any broad population decline, suggesting that presence of baits did not lead to loss of population viability.
Several problems encountered during the study affected the results:
• The visual lures used with the automated camera surveys were not ideal.
• The baiting aircraft was delayed, which meant that baits were applied in hotter weather. This affected increases in both the desiccation rate of baits and potentially also the abundance of available prey resource particularly with small reptiles.
• Baits developed a putrescent odour and exhibited limited ‘sweating’ (i.e. exudation of the chicken fat component) which reduced bait attractiveness.
• Insufficient cats were fitted with collars to make confident statements about changes in the feral cat population.
Ongoing development efforts are required to confirm that the Curiosity bait efficacy is an effective management tool for reducing feral cat populations in semi-arid Australia.