Are red-tailed phascogales (Phascogale calura) at risk from Eradicat® cat baits?

Abstract

ContextFeral cats have benefitted from effective control of foxes in south-western Australia and, consequently, their impact on some threatened mammal species has increased. Control of feral cats in the region can be enhanced by use of the Eradicat® cat bait, but its impact on non-target animal populations requires investigation before widespread use. AimsThe aim of the present study was to determine through field trials whether consumption of Eradicat® baits by resident red-tailed phascogales, following a broadscale baiting operation to control feral cats, was sufficiently frequent to cause significant rates of mortality in wild populations of phascogales. MethodsNine radio-tagged red-tailed phascogales were monitored through an Eradicat® baiting event to determine their survival. Removal and consumption of toxic and non-toxic rhodamine B-labelled baits by a range of species were monitored with camera traps and by subsequent trapping of red-tailed phascogales and other mammals to sample whiskers for evidence of rhodamine uptake. Key resultsAlthough some phascogales showed interest in baits and sometimes moved them from the deposition site, all radio-tagged phascogales survived for at least 1 week after baiting, by which time very few or no baits remained. Examination of whiskers sampled from individuals exposed to rhodamine-labelled baits showed that consumption of non-toxic Eradicat® baits by phascogales was negligible; only one phascogale of 62 sampled showed any rhodamine banding. ConclusionsThe present study provided no evidence that red-tailed phascogales in the study region are at risk from an Eradicat® baiting episode in autumn. ImplicationsThe risk to red-tailed phascogale populations through the use of Eradicat® baiting to control cats in their habitat in the Great Southern region of Western Australia is likely to be low. Further research to elucidate any impact of repeated baiting on populations of this species at several locations is recommended.

The ecological costs and benefits of a feral cat poison‐baiting programme for protection of reintroduced populations of the western quoll and brushtail possum

“…2011; Friend 2013) but low for other taxa such as phascogales (Friend et al . 2020). The LD50 (lethal dose 50%) for the western quoll is 7.5 mg kg −1 of 1080 (approximately 2 Eradicat baits) (King et al .…”

Experimentally testing the response of feral cats and their prey to poison baiting

“…Many other studies have also recorded high non-target uptake of cat baits, including 22% of baits at Peron Peninsula (Algar et al 2007), 14-57% at Arid Recovery ), 71% at Kangaroo Island (Hohnen et al 2020), and 97% at Dryandra and Tutanning (Friend et al 2020). Only one of those studies recorded emus removing baits (Algar et al 2007), although it is not clear what proportion of baits were interfered with.…”

Cat ecology, impacts and management in Australia

“…However, the utility of Eradicat elsewhere in Australia depends on several factors, including the likelihood that native animals without this elevated tolerance will consume the baits. Several papers in the special issue build the body of evidence for when Eradicat can and cannot be safely used, with studies of the extent of nontarget impacts in south-western Australia (Friend et al 2020), the Pilbara (Cowan et al 2020) and Kangaroo Island (Hohnen et al 2020b).…”