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.

Dietary changes in response to population reduction in the possum Trichosurus vulpecula in New Zealand

2013 ◽  
Vol 40 (7) ◽  
pp. 561 ◽  
Author(s):  
Peter J. Sweetapple ◽  
Wendy A. Ruscoe ◽  
Graham Nugent
Keyword(s):  
New Zealand ◽  
Pest Control ◽  
Population Control ◽  
Stomach Contents ◽  
Brushtail Possum ◽  
Trichosurus Vulpecula ◽  
Dietary Changes ◽  
Before And After ◽  
Per Capita ◽  
Indigenous Forest

Context Efforts to protect or restore degraded plant communities by population control of invasive herbivores frequently fail to achieve their goals. Aims We seek to quantify changes in diet of an introduced herbivore, the brushtail possum (Trichosurus vulpecula), following population control, and determine how these may contribute to variable responses in plant condition. Methods Stomach contents of possums from five areas of indigenous forest in northern New Zealand were analysed to measure diet before and after the application of possum control. Key results The contribution of fruit, and foliage of some early successional forest species, to total possum diet increased up to 27-fold following possum population control. This was accompanied by declines in consumption of the main pre-control possum foods (foliage from common canopy trees). Dietary changes were a combination of an immediate response to control (1 year) and a strengthening of these initial changes with increasing time since control. Conclusions Possums in the study areas changed diet following population control, from a diet dominated by foliage of common canopy tree species to one dominated by fruits, and foliage of uncommon early successional plants. Pest control instantaneously increased the per capita availability of all foods, and probably permitted absolute increases in some foods through plant recovery, enabling possums to substitute scarce, high-preference foods for abundant but less preferred canopy foliage. Implications Following control of a pest herbivore, dietary changes reduce benefits for the most vulnerable preferred plant foods, but enhance benefits for less favoured plants. Intense pest control can permit some recovery of highly preferred foods, despite increased per capita consumption of these foods by survivors of control.

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.

Persistence of Sodium Monofluoroacetate in Livestock Animals and Risk to Humans

1994 ◽  
Vol 13 (2) ◽  
pp. 119-122 ◽  
Author(s):  
C.T. Eason ◽  
R. Gooneratnel ◽  
H. Fitzgerald ◽  
G. Wright ◽  
C. Frampton
Keyword(s):  
Body Weight ◽  
New Zealand ◽  
Pest Control ◽  
The Body ◽  
Sublethal Dose ◽  
Human Consumption ◽  
Accidental Exposure ◽  
Secondary Poisoning ◽  
Elimination Half ◽  
Liver And Kidney

1 Sodium monofluoroacetate (1080), a vertebrate pesticide widely used in New Zealand, was administered orally to sheep and goats at a dose level of 0.1 mg kg-1 body weight to assess risk to humans of secondary poisoning from meat. Blood, muscle, liver, and kidney were analysed for 1080 residues. 2 The plasma elimination half-life was 10.8 h in sheep and 5.4 h in goats. Concentrations of 1080 in muscle (0.042 ?g g-1), kidney (0.057 ?g g-1), and liver (0.021 ?g g-1) were substantially lower than those in plasma (0.098 ?g m-1) at 2.5 h after dosing. 3 Only traces of 1080 (<0.002 to 0.008 ?g g-1) were found in sheep tissues after 96 hours. 4 Livestock are normally excluded from areas where 1080 is being used for pest control, reducing the risk of secondary poisoning. Even with accidental exposure to a sublethal dose 1080 would not persist in tissues for more than a few days because it is cleared rapidly from the body. Therefore the occurrence of 1080 in meat intended for human consumption is highly unlikely.

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.

Routine blood values for New Zealand brushtail possums (Trichosurus vulpecula) at capture

1998 ◽  
Vol 46 (1) ◽  
pp. 41-42 ◽  
Author(s):  
J.S. O'Keefe ◽  
M. Wickstrom
Keyword(s):  
New Zealand ◽  
Trichosurus Vulpecula ◽  
Routine Blood

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

Energy Inputs In Pest Control Using Pesticides In New Zealand

2014 ◽  
pp. 99-126
Author(s):  
Majeed Safa ◽  
Meriel Watts
Keyword(s):  
New Zealand ◽  
Pest Control ◽  
Energy Inputs
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