Assessment of the M-44 ejector for the delivery of 1080 for red fox (Vulpes vulpes) control

Abstract

The M-44 ejector delivered a reliable lethal dose of 1080 (sodium monofluoroacetate) to captive foxes, with a capsule dose of 2.0 mg of 1080, if a ‘collar’ modification was used. Behavioural observations indicated that the collar influenced the orientation of the fox’s mouth to the M-44 bait upon activation, resulting in a much greater amount of 1080 entering its mouth. This dose is below the 3 mg currently used in fox baits in Victoria and may increase the margin of safety for non-target species during 1080 baiting programs. The authors discuss some of the potential advantages of the ejector over the use of meat baits, such as the elimination of bait caching and improved target specificity. The potential for the M-44 to deliver an even lower lethal dose of 1080, which is closer to the reported theoretical bait LD₁₀₀ of 1.25 mg for this species, may further reduce the risk of 1080 baiting to non-target species such as tiger quolls.