Potential impacts of poison baiting for introduced house mice on native animals on islands in Jurien Bay, Western Australia

Context House mice (Mus domesticus) are present on Boullanger and Whitlock islands, Western Australia, and could potentially threaten populations of the dibbler (Parantechinus apicalis) and grey-bellied dunnart (Sminthopsis griseoventer) through competition for resources. A workshop in 2007 recommended a study to assess the feasibility of eradicating house mice from the islands by using poison baits and of the risk posed to non-target native species. Aim We aimed to assess the risk to non-target native species if poison baiting was used to eradicate house mice on Boullanger and Whitlock islands. Methods Non-toxic baits containing the bait marker rhodamine B were distributed on Boullanger Island and on the mouse free Escape Island to determine the potential for primary poisoning. Acceptance of baits by mammals was measured through sampling and analysis of whiskers, and by reptiles through observations of dye in faeces. To determine the potential for secondary exposure to poison, the response of dibblers to mouse carcasses was observed using motion-activated cameras. Bait acceptance was compared using two methods of delivery, namely, scattering in the open and delivery in polyvinyl chloride (PVC) tubes. A cafeteria experiment of bait consumption by dibblers was also undertaken using captive animals held at the Perth Zoo. Ten dibblers were offered non-toxic baits containing rhodamine B in addition to their normal meals; consumption of bait and the presence of dye in whiskers were measured. Key results Bait acceptance on the islands was high for house mice (92% of individuals) and dibblers (48%) and it was independent of bait-delivery technique. There was no evidence of bait acceptance by grey-bellied dunnarts. Dibblers may consume mice carcasses if available; however, no direct consumption of mice carcasses was observed with movement sensor cameras but one dibbler was observed removing a mouse carcass and taking it away. During the cafeteria experiment, 9 of 10 captive dibblers consumed baits. Conclusions This investigation demonstrated that dibblers consume baits readily and island populations would experience high mortality if exposed to poison baits. Poison baiting could effectively eradicate mice from Boullanger and Whitlock islands but not without mortality for dibblers. Implications Toxic baits could be used to eradicate mice from Boullanger and Whitlock islands, provided that non-target species such as dibblers were temporarily removed from the islands before the application of baits.

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Bait consumption by, and 1080-based control of, feral pigs in the Mediterranean climatic region of south-western Australia

Wildlife Research ◽

10.1071/wr06084 ◽

2007 ◽

Vol 34 (2) ◽

pp. 125 ◽

Cited By ~ 7

Author(s):

Laurie E. Twigg ◽

Tim Lowe ◽

Gary Martin

Keyword(s):

Western Australia ◽

Sus Scrofa ◽

Native Species ◽

Target Species ◽

Variable Response ◽

Feral Pigs ◽

Poison Baiting ◽

The Mediterranean ◽

Bait Stations ◽

Minimal Evidence

The consumption of five non-toxic, grain-based baits, and the effectiveness of the preferred baits when treated with 1080 in reducing pig numbers, were determined for feral pigs (Sus scrofa) in several areas in the Mediterranean agricultural region of Western Australia. Fermented wheat with added blood and bone proved an effective attractant for feral pigs, and for determining areas of pig activity. Wheat and malted barley were the preferred baits, there was a variable response to lupins, and commercial pig pellets were consumed least. Malted barley, barley, and wheat treated with 1080 gave good reductions in pig numbers at the localised scale. Where pigs would eat lupins, 1080-treated lupins were usually effective in reducing pig abundance. In some instances, further evidence of feral pig activity was not seen on several sites for several months after poison-baiting occurred. The addition of a small amount of unpoisoned grain to mask the presence of 1080 did not increase the take of treated bait (P < 0.05). Although finding poisoned pigs was difficult owing to the terrain and the presence of bush remnants, the poisoned pigs found (n = 90) were often within 200 m of active bait stations. 1080-poisoned pigs included both adult (≥25 kg) and non-adult pigs of both sexes. Body mass of these pigs ranged from 4 to 90 kg. In all, 42% of poisoned adults found (n = 50) were 50 kg or more. There was minimal evidence of bait take by non-target species, and, where this occurred, it generally involved the consumption of the fermented wheat attractant by kangaroos (Macropus spp.) and foxes (Vulpes vulpes). Six foxes were known to have been poisoned with 1080-treated grain (4 with malted barley, 2 with wheat). Excluding foxes, no other non-target animals, including native species, were found dead during the intensive searches for poisoned pigs.

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Assessment of risks to non-target species from an encapsulated toxin in a bait proposed for control of feral cats

Wildlife Research ◽

10.1071/wr10105 ◽

2011 ◽

Vol 38 (1) ◽

pp. 39 ◽

Cited By ~ 6

Author(s):

Paul J. de Tores ◽

Duncan R. Sutherland ◽

Judy R. Clarke ◽

Robert F. Hill ◽

Sean W. Garretson ◽

...

Keyword(s):

Western Australia ◽

Rhodamine B ◽

Native Species ◽

Field Trials ◽

Target Species ◽

Mammal Species ◽

Current Form ◽

Feral Cat ◽

Feral Cats ◽

South West

Context The CURIOSITY® bait is the name coined for a variation of the existing sausage-style cat bait, ERADICAT®. The latter is used under experimental permit in Western Australia for research associated with cat control. The CURIOSITY bait differs from ERADICAT by providing a pH-buffered (less acidic) medium and has been proposed to reduce the risk to non-target species by encapsulating a toxin in a pellet. We trialled a prototype pellet proposed for encapsulation of 1080 and/or alternative toxins, with delivery proposed through the CURIOSITY bait. Aim Our aim was to determine whether the pellet was consumed by non-target native species from south-west of Western Australia. Methods Trials involved use of a non-toxic biomarker, Rhodamine B, encapsulated within the pellet and inserted into the CURIOSITY® bait. Uptake of the encapsulated biomarker was assessed in captive trials for the target species, the feral cat (Felis catus) and two non-target species of varanid lizard, Rosenberg’s goanna (Varanus rosenbergi) and Gould’s goanna (V. gouldii) and the non-target mammal species chuditch (Dasyurus geoffroii) and southern brown bandicoot (Isoodon obesulus). Uptake of the encapsulated biomarker was also assessed in field trials for a range of native species. Key results Captive trials demonstrated feral cats will consume the CURIOSITY bait and pellet. However, results from captive and field trials indicated several non-target species also consumed the bait and pellet. We also found the pellet itself was not sufficiently robust for use in a bait. As with previously reported studies, we found Rhodamine B to be an effective biomarker for use in cats. We also developed a technique whereby Rhodamine B can be used as a biomarker in reptiles. However, its use as a biomarker in other mammalian species was confounded by what appeared to be background, or pre-existing, levels of fluorescence, or banding, in their whiskers. Conclusion The prototype pellet is unsuitable in its current form for use with the CURIOSITY bait. We caution that the CURIOSITY bait has non-target issues in south-west of Western Australia and any proposed variations to this bait, or the ERADICAT® bait, need to be rigorously assessed for their potential risk to non-target species and assessed for the level of uptake by cats, irrespective of their suitability/unsuitability as a medium for delivery of an encapsulated toxin. We believe the threat to biodiversity-conservation values from unmitigated feral-cat predation of native fauna poses a significant and real threat and we recommend urgent investment of resources to address the issue of cat predation in a coordinated and collaborative manner within Australia and New Zealand.

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Uptake of ‘Eradicat’ feral cat baits by non-target species on Kangaroo Island

Wildlife Research ◽

10.1071/wr19056 ◽

2020 ◽

Vol 47 (8) ◽

pp. 547

Author(s):

Rosemary Hohnen ◽

Brett P. Murphy ◽

Sarah M. Legge ◽

Chris R. Dickman ◽

John C. Z. Woinarski

Keyword(s):

Rhodamine B ◽

Native Species ◽

South Australia ◽

Brushtail Possum ◽

Target Species ◽

Feral Cat ◽

Remote Cameras ◽

Poison Baiting ◽

Common Brushtail Possum ◽

Potential Impact

Abstract ContextPredation by feral cats (Felis catus) threatens a range of vertebrate species across Australia, and cat-free islands increasingly act as safe havens for biodiversity. A feral cat eradication program has begun on Kangaroo Island (4405km2) in South Australia, and poison baiting is likely to be one of the main methods used. Aims Here, we trial a non-toxic version of a cat bait, ‘Eradicat’, on western Kangaroo Island, to examine its potential impact on non-target species. MethodsNon-toxic baits containing the biomarker Rhodamine B were deployed across four sites in early August and late November in 2018, with bait take and consumption assessed both by remote cameras and by the presence of Rhodamine B in mammalian whisker samples taken post-baiting. Key resultsCats encountered baits on very few occasions and took a bait on only one occasion in August (<1% of 576 baits deployed). Non-target species accounted for over 99% of identifiable bait takes. In both seasons, >60% of all baits laid was taken by either the common brushtail possum (Trichosurus vulpecula), bush rat (Rattus fuscipes) or Australian raven (Corvus coronoides). In November, Rosenberg’s goanna (Varanus rosenbergi) and southern brown bandicoot (south-eastern subspecies; Isoodon obesulus obesulus), listed nationally as Endangered, also took baits (3% and 1% respectively). The Kangaroo Island dunnart (Sminthopsis fuliginosus aitkeni), listed nationally as endangered, approached a bait on only one occasion, but did not consume it. Evidence of bait consumption was visible in the whiskers of captured common brushtail possums (100% of post-baiting captured individuals in August, 80% in November), bush rats (59% in August and 50% in November), house mice (Mus musculus) (45% in November) and western pygmy-possums (Cercartetus concinnus) (33% in November). ConclusionsAlthough feral cat baiting has the potential to significantly benefit wildlife on Kangaroo Island, impacts on non-target species (particularly the bush rat and common brushtail possum) may be high. ImplicationsAlternative cat baits, such as those containing a toxin to which native species have a higher tolerance or that are less readily consumed by native wildlife, will be more appropriate.

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Evaluation of risks for two native mammal species from feral cat baiting in monsoonal tropical northern Australia

Wildlife Research ◽

10.1071/wr17171 ◽

2018 ◽

Vol 45 (6) ◽

pp. 518 ◽

Cited By ~ 3

Author(s):

Jaime Heiniger ◽

Skye F. Cameron ◽

Graeme Gillespie

Keyword(s):

Rhodamine B ◽

Native Species ◽

Field Trials ◽

Camera Traps ◽

Northern Australia ◽

Target Species ◽

Mammal Species ◽

Feral Cat ◽

Feral Cats ◽

Dry Tropics

Context Feral cats are a significant threat to native wildlife and broad-scale control is required to reduce their impacts. Two toxic baits developed for feral cats, Curiosity® and Hisstory®, have been designed to reduce the risk of baiting to certain non-target species. These baits involve encapsulating the toxin within a hard-shelled delivery vehicle (HSDV) and placing it within a meat attractant. Native animals that chew their food more thoroughly are predicted to avoid poisoning by eating around the HSDV. This prediction has not been tested on wild native mammals in the monsoonal wet–dry tropics of the Northern Territory. Aim The aim of this research was to determine whether northern quolls (Dasyurus hallucatus) and northern brown bandicoots (Isoodon macrourus) would take feral cat baits and ingest the HSDV under natural conditions on Groote Eylandt. Methods We hand-deployed 120 non-toxic baits with a HSDV that contained a biomarker, Rhodamine B, which stains animal whiskers when ingested. The species responsible for bait removal was determined with camera traps, and HSDV ingestion was measured by evaluating Rhodamine B in whiskers removed from animals trapped after baiting. Key results During field trials, 95% of baits were removed within 5 days. Using camera-trap images, we identified the species responsible for taking baits on 65 occasions. All 65 confirmed takes were by native species, with northern quolls taking 42 baits and northern brown bandicoots taking 17. No quolls and only one bandicoot ingested the HSDV. Conclusion The use of the HSDV reduces the potential for quolls and bandicoots to ingest a toxin when they consume feral cat baits. However, high bait uptake by non-target species may reduce the efficacy of cat baiting in some areas. Implications The present study highlighted that in the monsoonal wet–dry tropics, encapsulated baits are likely to minimise poisoning risk to certain native species that would otherwise eat meat baits. However, further research may be required to evaluate risks to other non-target species. Given the threat to biodiversity from feral cats, we see it as critical to continue testing Hisstory® and Curiosity® in live-baiting trials in northern Australia.

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Water and sodium requirements of field populations of house mice ( Mus domesticus ) and short-tailed mice ( Leggadina lakedownensis ) on Thevenard Island, in the arid Pilbara region of Western Australia

Journal of Comparative Physiology B ◽

10.1007/s003600050238 ◽

1999 ◽

Vol 169 (6) ◽

pp. 419-428 ◽

Cited By ~ 3

Author(s):

D. Moro ◽

S. D. Bradshaw

Keyword(s):

Western Australia ◽

House Mice ◽

Mus Domesticus

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Drivers of predatory behavior and extreme size in house mice Mus musculus on Gough Island

Journal of Mammalogy ◽

10.1093/jmammal/gyv199 ◽

2016 ◽

Vol 97 (2) ◽

pp. 533-544 ◽

Cited By ~ 19

Author(s):

Richard J. Cuthbert ◽

Ross M. Wanless ◽

Andrea Angel ◽

Marie-Helene Burle ◽

Geoff M. Hilton ◽

...

Keyword(s):

Body Mass ◽

Mus Musculus ◽

Native Species ◽

Predatory Behavior ◽

House Mice ◽

Mouse Population ◽

Island Populations ◽

Gough Island ◽

Mammalian Predators ◽

Island Syndrome

Abstract In comparison to the mainland, populations of rodents on islands are often characterized by a suite of life history characteristics termed the “island syndrome.” Populations of rodents introduced to islands are also well known for their impacts on native species that have evolved in the absence of mammalian predators. We studied the ecology and behavior of introduced house mice Mus musculus on Gough Island where they are the only terrestrial mammal and where their predatory behavior is having a devastating impact on the island’s burrowing petrel (order Procellariiformes ) population and the Critically Endangered Tristan albatross Diomedea dabbenena . Mice on Gough exhibit extreme features of the island syndrome, including: a body mass 50–60% greater than any other island mouse population, peak densities among the highest recorded for island populations, and low seasonal variation in numbers compared to other studied islands. Seasonal patterns of breeding and survival were linked to body condition and mass, and mice in areas with high chick predation rates were able to maintain higher mass and condition during the winter when mouse mortality rates peak. Within-site patterns of chick predation indicate that proximity to neighboring predated nests and nesting densities are important factors in determining the likelihood of predation. We conclude that selection for extreme body mass and predatory behavior of mice result from enhanced overwinter survival. Small mammal populations at temperate and high latitudes are normally limited by high mortality during the winter, but on Gough Island mice avoid that by exploiting the island’s abundant seabird chicks.

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Mus musculus populations in Western Australia lack VKORC1 mutations conferring resistance to first generation anticoagulant rodenticides: Implications for conservation and biosecurity

10.1101/2020.07.06.189282 ◽

2020 ◽

Author(s):

Bridget J.M.L. Duncan ◽

Annette Koenders ◽

Quinton Burnham ◽

Michael T. Lohr

Keyword(s):

House Mouse ◽

Western Australia ◽

Mus Musculus ◽

House Mice ◽

Target Species ◽

Mouse Population ◽

Anticoagulant Rodenticides ◽

D Loop ◽

Rodent Populations ◽

Vkorc1 Gene

AbstractBackgroundHumans routinely attempt to manage pest rodent populations with anticoagulant rodenticides (ARs). We require information on resistance to ARs within rodent populations to have effective eradication programs that minimise exposure in non-target species. Mutations to the VKORC1 gene have been shown to confer resistance in rodents with high proportions of resistance in mice found in all European populations tested. We screened mutations in Mus musculus within Western Australia, by sampling populations from the capital city (Perth) and a remote island (Browse Island). These are the first Australian mouse populations screened for resistance using this method. Additionally, the mitochondrial D-loop of house mice was sequenced to explore population genetic structure, identify the origin of Western Australian mice, and to elucidate whether resistance was linked to certain haplotypes.ResultsNo resistance-related VKORC1 mutations were detected in either house mouse population. A genetic introgression in the intronic sequence of the VKORC1 gene of Browse Island house mouse was detected which is thought to have originated through hybridisation with the Algerian mouse (Mus spretus). Analysis of the mitochondrial D-loop reported two haplotypes in the house mouse population of Perth, and two haplotypes in the population of Browse Island.ConclusionsBoth house mouse populations exhibited no genetic resistance to ARs, in spite of free use of ARs in Western Australia. Therefore weaker anticoagulant rodenticides can be employed in pest control and eradication attempts, which will result in reduced negative impacts on non-target species. Biosecurity measures must be in place to avoid introduction of resistant house mice, and new house mouse subspecies to Western Australia.

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