Field assessment of the risk of feral cat baits to non-target species in eastern Australia

Abstract

Feral cats pose a significant threat to wildlife, agriculture and human health through predation, disease transmission and competition with native animals. Controlling feral cats and their impacts, however, is challenging. New and emerging 1080-based feral cat baits have shown promising results in western and central Australia, however the safety of these new baits for non-target species in eastern Australia, where many native animals are more sensitive to 1080 than their western conspecifics, has not been assessed. We investigated the uptake by non-target animals of 499 toxic Eradicat® baits across five different eastern Australian environs, and the uptake of non-toxic Eradicat® and Hisstory® baits at an additional two sites. Using field-based observations of species eating or removing baits, we determined that 13 non-target species (eight mammals, four birds, one reptile) were at high risk of individual mortality, with individuals of 11 of those 13 species (four birds, seven mammals) observed consuming enough toxic Eradicat® in a single visit to ingest a lethal dose of 1080. Feral cats (the target species) consumed only 3.1% of monitored baits, which was only 52% of the 31 baits they encountered. We recommend undertaking targeted population monitoring of species identified at high risk of individual mortality, to determine whether Eradicat® baits present a population-level risk to these species. Our findings suggest that the small-sized Eradicat® baits present a greater risk to non-target species in eastern Australia than the larger traditional 1080-based meat baits used for the control of wild dogs and foxes. Our study highlights the importance of performing risk assessments for different bait types, even when the same toxin is used, and of performing site-specific non-target risk assessments of new baits such as Eradicat® to assist developing guidelines for their safe and effective use in different environs. This article is protected by copyright. All rights reserved.