Effect of prefeeding, sowing rate and sowing pattern on efficacy of aerial 1080 poisoning of small-mammal pests in New Zealand

Graham Nugent, Bruce Warburton, Caroline Thomson, Peter Sweetapple, Wendy RUSCOE

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Context. Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim. The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods. Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus rattus) and mouse (Mus musculus). Key results. Outcomes were highly variable, ranging from increases in pest activity to near total reductions. Possum reductions were highest where one or two prefeeds were used, and at the higher sowing rates (2 or 5 kg/ha), but with some interactions between these factors. For rats, two prefeeds resulted in the highest reductions but sowing rate had no effect. For mice, post-poisoning indices were often high, indicating low effectiveness. Conclusions. Some treatments were highly effective so poor kills were unlikely to have resulted from pests not encountering bait, or the bait being unpalatable. Rather they appeared to reflect sub-lethal poisoning either as a result of low acceptance (as a result of a lack of familiarity and/or satiation) or bait fragmentation. We infer that for possum and rats prefeeding helps reduce this risk of sub-lethal poisoning not only by increasing familiarity, but also (in conjunction with high sowing rates) by increasing the bait encounter rate, particularly for possums. Implications. There is scope to further reduce the amount of toxic bait sown and the cost of poisoning, without compromising efficacy, by fine-tuning the balance between prefeeding and sowing rate based on which species are being targeted and, for possums, reducing bait fragmentation.
Original languageEnglish
Pages (from-to)249-259
Number of pages11
JournalWildlife Research
Volume38
DOIs
Publication statusPublished - 2011
Externally publishedYes

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bait
small mammal
poisoning
small mammals
sowing
baits
pests
familiarity
rats
fragmentation
sodium fluoroacetate
Trichosurus vulpecula
Rattus rattus
encounter rate
rate
effect
pest
lethal dose
mice
Mus musculus

Cite this

Nugent, Graham ; Warburton, Bruce ; Thomson, Caroline ; Sweetapple, Peter ; RUSCOE, Wendy. / Effect of prefeeding, sowing rate and sowing pattern on efficacy of aerial 1080 poisoning of small-mammal pests in New Zealand. In: Wildlife Research. 2011 ; Vol. 38. pp. 249-259.
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abstract = "Context. Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim. The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods. Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus rattus) and mouse (Mus musculus). Key results. Outcomes were highly variable, ranging from increases in pest activity to near total reductions. Possum reductions were highest where one or two prefeeds were used, and at the higher sowing rates (2 or 5 kg/ha), but with some interactions between these factors. For rats, two prefeeds resulted in the highest reductions but sowing rate had no effect. For mice, post-poisoning indices were often high, indicating low effectiveness. Conclusions. Some treatments were highly effective so poor kills were unlikely to have resulted from pests not encountering bait, or the bait being unpalatable. Rather they appeared to reflect sub-lethal poisoning either as a result of low acceptance (as a result of a lack of familiarity and/or satiation) or bait fragmentation. We infer that for possum and rats prefeeding helps reduce this risk of sub-lethal poisoning not only by increasing familiarity, but also (in conjunction with high sowing rates) by increasing the bait encounter rate, particularly for possums. Implications. There is scope to further reduce the amount of toxic bait sown and the cost of poisoning, without compromising efficacy, by fine-tuning the balance between prefeeding and sowing rate based on which species are being targeted and, for possums, reducing bait fragmentation.",
keywords = "bait fragmentation, brushtail possums, mice, Mus musculus, Rattus rattus, sodium fluoroacetate, ship rats, Trichosurus vulpecula.",
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Effect of prefeeding, sowing rate and sowing pattern on efficacy of aerial 1080 poisoning of small-mammal pests in New Zealand. / Nugent, Graham; Warburton, Bruce; Thomson, Caroline; Sweetapple, Peter; RUSCOE, Wendy.

In: Wildlife Research, Vol. 38, 2011, p. 249-259.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of prefeeding, sowing rate and sowing pattern on efficacy of aerial 1080 poisoning of small-mammal pests in New Zealand

AU - Nugent, Graham

AU - Warburton, Bruce

AU - Thomson, Caroline

AU - Sweetapple, Peter

AU - RUSCOE, Wendy

PY - 2011

Y1 - 2011

N2 - Context. Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim. The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods. Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus rattus) and mouse (Mus musculus). Key results. Outcomes were highly variable, ranging from increases in pest activity to near total reductions. Possum reductions were highest where one or two prefeeds were used, and at the higher sowing rates (2 or 5 kg/ha), but with some interactions between these factors. For rats, two prefeeds resulted in the highest reductions but sowing rate had no effect. For mice, post-poisoning indices were often high, indicating low effectiveness. Conclusions. Some treatments were highly effective so poor kills were unlikely to have resulted from pests not encountering bait, or the bait being unpalatable. Rather they appeared to reflect sub-lethal poisoning either as a result of low acceptance (as a result of a lack of familiarity and/or satiation) or bait fragmentation. We infer that for possum and rats prefeeding helps reduce this risk of sub-lethal poisoning not only by increasing familiarity, but also (in conjunction with high sowing rates) by increasing the bait encounter rate, particularly for possums. Implications. There is scope to further reduce the amount of toxic bait sown and the cost of poisoning, without compromising efficacy, by fine-tuning the balance between prefeeding and sowing rate based on which species are being targeted and, for possums, reducing bait fragmentation.

AB - Context. Aerial poisoning using sodium fluoroacetate (1080) is an important but controversial technique used for large-scale control of brushtail possums (Trichosurus vulpecula) and other pests in New Zealand. The technique reliably produces near total kills of possums and rats, provided that many tens of baits (and therefore many tens of individually lethal doses) are sown for each target animal present. Aim. The aim of this study was to further refine aerial 1080 poisoning by determining the effect of prefeeding, sowing rate, and sowing pattern on effectiveness. Methods. Eighteen experimental treatments comprising all possible combinations of three sowing rates (1, 2, and 5 kg/ha of bait), three frequencies of non-toxic prefeed (0, 1, and 2) and two sowing patterns (parallel and cross-hatched) were applied to each of two forested areas. Treatment effectiveness was assessed from changes in the rate of interference recorded on baited cards for three species: possum, ship rat (Rattus rattus) and mouse (Mus musculus). Key results. Outcomes were highly variable, ranging from increases in pest activity to near total reductions. Possum reductions were highest where one or two prefeeds were used, and at the higher sowing rates (2 or 5 kg/ha), but with some interactions between these factors. For rats, two prefeeds resulted in the highest reductions but sowing rate had no effect. For mice, post-poisoning indices were often high, indicating low effectiveness. Conclusions. Some treatments were highly effective so poor kills were unlikely to have resulted from pests not encountering bait, or the bait being unpalatable. Rather they appeared to reflect sub-lethal poisoning either as a result of low acceptance (as a result of a lack of familiarity and/or satiation) or bait fragmentation. We infer that for possum and rats prefeeding helps reduce this risk of sub-lethal poisoning not only by increasing familiarity, but also (in conjunction with high sowing rates) by increasing the bait encounter rate, particularly for possums. Implications. There is scope to further reduce the amount of toxic bait sown and the cost of poisoning, without compromising efficacy, by fine-tuning the balance between prefeeding and sowing rate based on which species are being targeted and, for possums, reducing bait fragmentation.

KW - bait fragmentation

KW - brushtail possums

KW - mice

KW - Mus musculus

KW - Rattus rattus

KW - sodium fluoroacetate

KW - ship rats

KW - Trichosurus vulpecula.

U2 - 10.1071/WR10198

DO - 10.1071/WR10198

M3 - Article

VL - 38

SP - 249

EP - 259

JO - Australian Wildlife Research

JF - Australian Wildlife Research

SN - 1035-3712

ER -