Induced 1080 Bait-Shyness in Captive Brushtail Possums and Implications for Management.

1996 ◽  
Vol 23 (2) ◽  
pp. 207 ◽  
Author(s):  
DR Morgan ◽  
G Morriss ◽  
GJ Hickling
Keyword(s):  
New Zealand ◽  
Sublethal Dose ◽  
Trichosurus Vulpecula

The probable cause of possums (Trichosurus vulpecula) becoming 'shy' towards 1080 [sodium fluoroacetate] bait, a growing problem in the control of this pest, was determined. Possums captured from North Canterbury, New Zealand, (n = 131) were offered sublethal baits (1 or 2.5 g) followed by lethal (6 g) baits 2 days later. Most possums became bait shy and the proportion becoming shy appeared to be related to the size of the initial sublethal dose. Most of a group of survivors retested after 3 months with toxic pellets were still shy. Shyness was not overcome by changing to a different mask (orange flavour, as opposed to cinnamon flavour) or toxin (brodifacoum), but changing to both a different bait base (carrot) and mask (orange) resulted in most shy possums eating a lethal quantity of bait. Possums therefore appeared to learn to recognise the bait base as the cue for avoiding poisoning. More shy possums than naive possums rejected non-dyed, non-masked, non-toxic pellets, confirming that shy possums recognised the bait base. Green dye appears to act as a secondary cue for avoiding pellets as a higher percentage of 'shy' possums than naive possums rejected dyed baits.

scholarly journals Implications of prefeeding for the development of bait aversions in brushtail possums (Trichosurus vulpecula)

1998 ◽  
Vol 25 (2) ◽  
pp. 133 ◽  
Author(s):  
Zane N. Moss ◽  
Cheryl E. O'Connor ◽  
Graham J. Hickling
Keyword(s):  
New Zealand ◽  
Pest Control ◽  
Subsequent Development ◽  
Sublethal Dose ◽  
Trichosurus Vulpecula ◽  
Management Procedure

Development of aversions, or learned ‘bait-shyness’, in frequently poisoned possum (Trichosurus vulpecula) populations is becoming increasingly detrimental to the efficacy of pest-control operations in New Zealand. This experiment aimed to identify the effects of prefeeding, a common management procedure, on the subsequent development of aversions in possums. Wild possums (n = 96) were captured and acclimatised, then allocated to one of three treatments groups that for seven days received either (i) no prefeed, (ii) plain RS5 cereal baits, or (iii) green-dyed and cinnamon-lured RS5 cereal baits. The possums were then offered a standard green-dyed and cinnamon-lured RS5 bait that contained a sublethal dose (0.4 mg kg-1) of the toxin sodium monofluoroacetate (1080). The possums were tested for development of an aversion towards a toxic RS5 1080 bait, a prefeed bait, and a prefeed bait containing an alternative toxin, brodifacoum. Most (96%) of the non-prefed possums became averse to the 1080 bait after two exposures, compared with only 55% and 9% of the two prefed groups. Similarly, 90% and 92% of the non-prefed possums were averse to prefeed and brodifacoum baits, respectively, compared with 8% and 14% of the prefed possums. This suggests that pest managers can reduce the risk of ‘bait shyness’ by prefeeding. A further advantage of prefeeding is that if poison shyness develops, use of an alternative toxin such as brodifacoum in the original bait base may still be successful.

Behaviour and time to unconsciousness of brushtail possums (Trichosurus vulpecula) after a lethal or sublethal dose of 1080

2009 ◽  
Vol 36 (8) ◽  
pp. 709 ◽  
Author(s):  
Kate E. Littin ◽  
Neville G. Gregory ◽  
Andrea T. Airey ◽  
Charles T. Eason ◽  
David J. Mellor
Keyword(s):  
New Zealand ◽  
Animal Welfare ◽  
Lethal Dose ◽  
Total Loss ◽  
Sublethal Dose ◽  
Loss Of Consciousness ◽  
Trichosurus Vulpecula ◽  
Welfare Impacts ◽  
Behavioural Changes ◽  
H 26

Context. Sodium fluoroacetate (1080) is a vertebrate pesticide used in several countries, including New Zealand, where it is the main pesticide for controlling brushtail possums (Trichosurus vulpecula) – a significant agricultural and conservation pest. There is growing concern internationally about the impacts of vertebrate pesticides, including 1080, on pest animal welfare. Aims. Behavioural changes and time to loss of consciousness of possums after 1080 ingestion in carrot baits were determined to compare the animal welfare impacts with other possum pesticides. Methods. Eight lethally dosed possums and eight that consumed a dose intended to be sublethal were observed until death or recovery but not handled. Another nine lethally dosed possums were handled to determine responses to stimuli, indicating time to loss of consciousness. Key results. Unhandled, lethally dosed possums died after 11 h 26 min ± 1 h 55 min (mean ± s.e.m.). Half had abnormal appearances and postures 1 h 50 min ± 9 min after consuming baits. Seven showed retching, and three vomited, over 27 ± 12 min from 2 h 53 min ± 13 min. Lack of coordination began 3 h 37 min ± 32 min after dosing, then possums spent most of the time until death lying, showing spasms and tremors. Five showed seizures while lying prostrate. Possums receiving a nominally sublethal dose all showed signs of poisoning, including abnormal postures, lethargy, lack coordination, retching, spasms or tremors, and a cessation of grooming, feeding and activity. One died 18 h 15 min after dosing, experiencing two seizures within 30 min of death. Response to handling, indicating total loss of consciousness, was lost in two possums before death. Conclusions. Possums ingesting a lethal dose of 1080 experienced ~9.5 h of changed behaviour and lost consciousness close to death, although awareness was likely reduced sometime beforehand. Possums ingesting a nominally sublethal dose experienced some effects of poisoning. Implications. These impacts are intermediate compared with other possum pesticides in New Zealand. Nevertheless, the potential for consciousness during and after retching and seizures is undesirable for animal welfare. Further work is encouraged on alternatives to 1080 and means of reducing its impact on animal welfare.

A systematic approach to evaluating and ranking the relative animal welfare impacts of wildlife control methods: poisons used for lethal control of brushtail possums (Trichosurus vulpecula) in New Zealand

2016 ◽  
Vol 43 (7) ◽  
pp. 553 ◽  
Author(s):  
N. J. Beausoleil ◽  
P. Fisher ◽  
K. E. Littin ◽  
B. Warburton ◽  
D. J. Mellor ◽  
...  
Keyword(s):  
New Zealand ◽  
Animal Welfare ◽  
Policy Development ◽  
Management Decision ◽  
Pest Species ◽  
Control Methods ◽  
Trichosurus Vulpecula ◽  
Welfare Impacts ◽  
Wildlife Control ◽  
Management Decision Making

Context Control of unwanted wildlife (‘pest’ animals) is undertaken for conservation and economic reasons, and when such animals are considered a nuisance. Such control should be undertaken using approaches that minimise, as far as possible, detrimental impacts on the welfare of the animals. Using a scientific framework based on the Five Domains model, the relative welfare impacts of pest control methods can be compared across methods and pest species. Aims We demonstrate the application of a modified version of this framework to evaluate the relative impacts of seven Vertebrate Toxic Agents (VTAs) used to control brushtail possums (Trichosurus vulpecula) in New Zealand. The evaluation is used to produce a ranking of the seven VTAs based on their relative impacts on possum welfare. Methods Scientific literature describing mode of toxic action, specific effects in possums or other animals and reports from human poisonings was collated as reference material for a panel of six experts. The panel produced a median welfare impact score (‘none’ to ‘extreme’) for each of the Five Domains. The ‘Overall Grade’ (1 to 8) reflected the intensity and duration of all impacts of a VTA on possums. Key results All VTAs evaluated have at least moderate impacts on possum welfare, lasting for at least minutes. Cyanide was assessed as having the lowest welfare impacts (median grade 4), and cholecalciferol and the anticoagulants the highest impacts (7.5 to 8). Zinc phosphide was assigned an intermediate grade (6) with high confidence. While the overall impacts of sodium fluoroacetate (1080) and phosphorus were also assessed as intermediate (6), the panel’s confidence in these scores was low. Conclusions From an animal welfare perspective, anticoagulant poisons and cholecalciferol should be the least preferred options for controlling possums in New Zealand, as VTAs with less severe welfare impacts are available. Implications The results of such assessments allow animal welfare impacts to be integrated with other factors in wildlife management decision-making and policy development, and are thus useful for managers, researchers, regulators and operators. Evaluation of welfare impacts aligns with the goals and mandates of ethical wildlife control and may also be valuable in wider wildlife research and management activities.

scholarly journals Ecology of a brushtail possum (Trichosurus vulpecula) population at Castlepoint in the Wairarapa, New Zealand

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Ron Jackson ◽  
D.U. Pfeiffe ◽  
T Porphyre ◽  
C Sauter-Louis ◽  
L.A.L. Corner ◽  
...  
Keyword(s):  
New Zealand ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula

Optimising bait size and 1080 concentration (sodium monofluoroacetate) for the control of brushtail possums Trichosurus vulpecula)

1999 ◽  
Vol 26 (1) ◽  
pp. 53 ◽  
Author(s):  
C. M. Frampton ◽  
B. Warburton ◽  
R. Henderson ◽  
D. R. Morgan
Keyword(s):  
New Zealand ◽  
Weight Distribution ◽  
Lethal Dose ◽  
Distribution Data ◽  
Trichosurus Vulpecula ◽  
Toxic Concentration ◽  
The Mean ◽  
Quantitative Assessments

A method is presented for quantitatively assessing the likely effectiveness of specific bait size and 1080 concentration for controlling brushtail possums with a known weight distribution. Data from aerial 1080 operations for the control of brushtail possums in New Zealand show that estimates of the bait size and toxic concentration required derived from the mean parameters [pest weight, bait size, and lethal dose (LD 95)] will not be accurate. This inaccuracy is most likely to lead to an underestimate of the amount of toxin presented to each animal, so that many operations currently run the risk of sub-lethally dosing possums and thereby possibly inducing some degree of poison shyness. On the basis of more accurate quantitative assessments of bait effectiveness we recommend that the 1080 concentration be increased to 0.15% and that baits less than 5 g be excluded to ensure that when mean possum weights are less than 3 kg more than 95% of possums are lethally dosed by a single bait.

Secondary poisoning of stoats (Mustela erminea) at low mouse (Mus musculus) abundance in a New Zealand Nothofagus forest

1998 ◽  
Vol 25 (4) ◽  
pp. 419 ◽  
Author(s):  
K. P. Brown ◽  
N. Alterio ◽  
H. Moller
Keyword(s):  
New Zealand ◽  
Mus Musculus ◽  
Prey Species ◽  
Rattus Rattus ◽  
Relative Importance ◽  
Trichosurus Vulpecula ◽  
Secondary Poisoning ◽  
Mustela Erminea ◽  
Nothofagus Forest ◽  
Tracking Tunnels

Two different brodifacoum (Talon 20 P™) poisoning regimes effectively killed 100% of resident radio-tagged stoats (Mustela erminea) by secondary poisoning in a New Zealand Nothofagus forest when mice (Mus musculus) were scarce. Resident possums (Trichosurus vulpecula) and ship rats (Rattus rattus) were also killed. The relative importance of different prey species as sources of poison for stoats has not been clearly identified but availability of poisoned prey will determine the efficacy of secondary poisoning in years of low prey abundance. Tracking tunnels did not accurately measure the decline in the stoat population and were probably influenced by immigrant stoats that were kill-trapped and contained high levels of poison. This study corroborates the findings of several other similar studies that secondary poisoning using brodifacoum effectively kills stoats.

scholarly journals Assessing Movements of Brushtail Possums (Trichosurus vulpecula) in Relation to Depopulated Buffer Zones for the Management of Wildlife Tuberculosis in New Zealand

PLoS ONE ◽  
2015 ◽  
Vol 10 (12) ◽  
pp. e0145636 ◽  
Author(s):  
Andrea E. Byrom ◽  
Dean P. Anderson ◽  
Morgan Coleman ◽  
Caroline Thomson ◽  
Martin L. Cross ◽  
...  
Keyword(s):  
New Zealand ◽  
Trichosurus Vulpecula ◽  
Buffer Zones
Sign in / Sign up

Export Citation Format

Share Document