First in, first served: uptake of 1080 poison fox baits in south-west Western Australia

Abstract

Context: In Western Australia, baits containing 1080 poison are widely used to control the red fox (Vulpes vulpes) for fauna conservation. Despite long-term (15-17 years) baiting programs, bait uptake by target and non-target species is largely unknown, but affects baiting efficacy. Aims:We examined bait uptake of 1080-poisoned fox baits laid according to current practice at seven riparian sites in the northern jarrah forest (of south-west Western Australia). There, intensive baiting regimes have been implemented for the protection of quokka (Setonix brachyurus) populations.Methods: Over 9 months, 299 Probait ® baits were monitored regularly to determine their persistence, and, at 142 of these, Reconyx HC500 remote cameras were used to identify the species taking baits.To compare bait uptake with species presence at these sites, we calculated an activity index for each species from the number of passes of animals in front of the cameras.Key results: The species taking baits was identified for 100 of the baits monitored with cameras, and, because of multiple species taking baits, 130 bait take incidents were recorded in total. The fate of 40 of the baits was not discernible and two baits were not removed. In all, 99% of baits monitored by cameras were taken by non-target species and quokkas took 48% of them. The majority of baits (62% of the total 299 monitored) were taken before or on the first night of deployment, and 95% of baits had been taken within 7 days. With the exception of feral pigs, which took more baits than predicted from their activity index at these sites, baits were taken in proportion to the activity index of species.Foxes were present at four of the seven sites, but only one fox was observed taking a bait. Conclusions:The high level of uptake of baits by non-target animals reflects their diversity and abundance at these sites, but also significantly reduces the availability of baits to control foxes.Implications: Strategies to reduce non-target bait uptake and increase bait availability for foxes are required.

Reduced efficacy of baiting programs for invasive species: some mechanisms and management implications

“…Berry et al 2013), the possibility of avoidance of baits by foxes has also been raised by various authors (e.g. van Polanen Petel et al 2001;Dundas et al 2014). Innate avoidance of baits can be selected for over successive baiting runs, which will quickly remove bold/explorative individuals from the population, rapidly shifting the population average towards more neophobic animals.…”

“…animals not previously exposed to persecution/baiting, and/or consisting of predominantly yearling dispersers), suggesting that long-term programs, using the same approach consistently, artificially select for innate bait avoidance traits in red foxes. Dundas et al (2014) reported foxes passing baits on camera on multiple occasions, suggesting that, even though they had located baits, they did not take them. A similar finding has been reported by Kinnear et al (2017).…”

“…Herbivores are generally assumed to avoid taking meat baits, although there is plenty of evidence that they do (e.g. Dundas et al 2014). Second, species may also have different toxin tolerance by virtue of the mode of action of the toxin.…”

“…Due to partial consumption Dundas et al 2014), many smaller animals that cannot consume a whole bait can interfere with the toxin dose present. For example, rodents may gnaw at baits, while invertebrates such as ants can also consume parts of the bait (Merks and Calver 1989).…”

“…Howard et al (1973) Red fox (Vulpes vulpes) 1080: e.g. Thompson and Fleming (1994); Hunt et al (2007); Dundas et al (2014); Kinnear et al (2017) N.D.…”