Comparative effects of brodifacoum on rats and possums

Littin, KE; O'Connor, C. E.; Eason, Charles

doi:10.30843/nzpp.2000.53.3701

Cited by 21 publications

(19 citation statements)

References 9 publications

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“…For example, while brodifacoum can exert toxicity following a single feeding event, mortality can lag significantly following the feeding event. Reports of time-to-death (in days) of some mammals following ingestion of toxic doses of brodifacoum were 5.6-8.5 for Norway rats (Rattus norvegicus), 14.9-45.3 for brushtail possum (Trichosurus vulpecula) (Littin et al 2000), and 2-18 for rabbits (Oryctolagus cuniculus; Godfrey et al 1981). If it is assumed that metabolic rate can play a role in manifestation of toxicity (in addition to toxicokinetic/ toxicodynamic causes), toxicity may manifest in our lizards after 14 days of exposure.…”

Section: Discussionmentioning

confidence: 99%

“…Longer observation may be especially important for some of the rodenticides tested, which may exhibit a lag between dosing and mortality (e.g. brodifacoum; Littin et al 2000). Any lizard that survived the 96 h short term observation period was then observed for an additional 10 days to score long-term response to the pesticide.…”

Section: Acute Toxicity Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Acute toxicity and risk to lizards of rodenticides and herbicides commonly used in New Zealand

Weir¹,

Yu²,

Knox³

et al. 2016

NZ J Ecol

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Invasive species can have negative consequences on native reptile populations, especially on island systems. Chemical control can be a cost-effective way to control or eradicate invasive species. Chemical control is currently in use in New Zealand to limit impacts of non-native mammals and plants on a range of native biodiversity. However, it is important to consider the potential non-target risks of chemical control to native species that are likely already significantly reduced in number. We aimed to characterise the toxicity of several rodenticides and herbicides to reptiles and to provide a screening-level risk assessment of these chemicals applicable to native reptiles of New Zealand using the western fence lizard, Sceloporus occidentalis, as a surrogate organism. We used the Up-and-Down testing procedure to estimate oral toxicity for all compounds. We tested five rodenticides (brodifacoum, coumatetralyl, pindone, diphacinone and cholecalciferol). Only pindone was toxic to fence lizards at concentrations below 1750 µg g-1 (LD50 = 550 µg g-1). We tested five herbicides (glyphosate, clopyralid, triclopyr, metsulfuron-methyl and haloxyfop-methyl) and one common adjuvant in glyphosate formulations (polyethoxylated tallowamine or POEA). Only triclopyr was toxic to fence lizards below 1750 µg g-1 (LD50 = 550 µg g-1). Toxicity does not necessarily imply risk. Using the pindone concentrations in accepted bait formulations in New Zealand, a 10 g lizard would need to ingest 4.7 g of pindone bait in a single day in order to achieve toxic levels, which is extremely unlikely. We used the highest acceptable application rate for triclopyr to estimate risk for reptiles and found minimal risk of acute toxicity from triclopyr applications. Taken together, our data suggest little risk of reptile acute toxicity from the tested rodenticides or herbicides in New Zealand, but research into sub-lethal effects is also required in order to make informed decisions about the ecological impacts of chemically controlling invasive species.

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Section: Discussionmentioning

confidence: 99%

Section: Acute Toxicity Experimentsmentioning

confidence: 99%

Acute toxicity and risk to lizards of rodenticides and herbicides commonly used in New Zealand

Weir¹,

Yu²,

Knox³

et al. 2016

NZ J Ecol

View full text Add to dashboard Cite

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“…The presence of this individual confirms that a female rat survived for much longer than expected. Rats have survived for up to 21 days after ingestion of a lethal dose in laboratory trials (Pitt 2004), but time to death is generally much shorter (Littin et al 2000). How and why did this female survive for so long?…”

Section: Discussionmentioning

confidence: 99%

The Wake Island Rodent Eradicaation – Part Success, Part Failure, but Wholly Instructive

Griffiths¹,

Wegmann²,

Hanson³

et al. 2014

vertebrate_pest_conference

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Rodent eradications undertaken on tropical islands have had a lower success rate than those attempted in temperate regions. A recent project undertaken to eradicate Rattus tanezumi and R. exulans from the 3 islands comprising Wake Atoll is illustrative. R. tanezumi was successfully removed from all 3 islands. R. exulans was permanently eradicated on Peale Island (95 ha) and temporarily on Wilkes Island (76 ha). R. exulans eradication on Wake Island (525 ha) was unsuccessful and the species has since repopulated Wake Island and recolonized Wilkes Island. We completed a detailed review of the project in an attempt to isolate potential causes of eradication failure. Based on the evidence available, we were not able to positively identify a single factor to explain why R. exulans survived on Wake Island. However, monitoring after the operation points to a sequence of events that comprised delayed mortality amongst a subset of breeding females and the emergence of young rats after bait was no longer readily available. Such an event was likely influenced by an abundance of natural food resources throughout the treatment area, a high density of rats, interspecific competition for toxic bait, and rapid disappearance of bait because of consumption by non-target consumers (land crabs). These factors are common to many tropical islands. We provide recommendations for addressing these factors in a future attempt to remove rats from Wake Atoll. Proc. 26 th Vertebr. Pest Conf. (R. M. Timm and J. M. O'Brien, Eds.) Published at Univ. of Calif., Davis. 2014. Pp. 101-111.

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“…The possum cautiously eats the bait, falsely learning that the bait is "safe," and nightly intake increases. Although outward symptoms of toxicosis are first seen at about 13-15 days (Littin et al 2000), the possum continues to consume the bait, often right up to the point of death (Morgan and Ross 2001) indicating that learned food-safety, like learned bait-shyness, is a very rigid behavior once formed. Brodifacoum baits have become regarded as a less desirable control option because they are relatively expensive, and because the toxicant is highly persistent in animal tissues, posing risks of secondary poisoning.…”

Section: Management Implicationsmentioning

confidence: 99%

Learned bait-shyness by possums (Trichosurus vulpecula) towards baits containing cyanide, 1080, cholecalciferol, or brodifacoum

Morgan¹,

Milne²,

O'Connor³

2002

vertebrate_pest_conference

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Around NZ$76 million per annum is presently spent on controlling and researching the introduced brushtail possum in New Zealand. The national control effort is likely to be further increased over the next decade in an attempt to eradicate bovine tuberculosis and to arrest the degradation of key conservation areas. There is a risk that repeated control operations using toxic baits could result in widespread development of learned "bait-shyness," behavior that develops when sublethally poisoned animals are able to link the experience of an illness with the memory of the bait eaten. Four studies are reviewed that aimed to determine the likelihood of possums becoming shy after sublethal doses imparted by different types of toxic bait, and to find solutions to the problem. Captive possums were presented with baits containing sublethal doses of the 4 vertebrate pesticides commonly used. Following a recovery period, possums were presented with lethal baits and their response compared with that of naive possums. Between 15% and 90% of possums previously dosed with sublethal doses of cyanide, 1080, or cholecalciferol developed baitshyness, the proportion being dose and toxicant dependent. Although cholecalciferol induces toxicosis more slowly (i.e., >24 h) than cyanide (5 min) and 1080 (1 h), possums were nevertheless able to associate the effects of this toxicant with consumption of the bait in which it was delivered and avoid eating further baits. However, brodifacoum acts very slowly (1-4 weeks), and possums did not become shy towards baits containing this toxicant after first eating sublethal baits. Shyness induced by either 1080 or cyanide persisted for at least 12 and 24 months respectively, thus jeopardizing the effectiveness of "maintenance" control operations, which can be required every 12 months or less. The persistence of bait-shyness to cholecalciferol remains untested. Use of alternative baits (bait-switching) proved an effective solution for eliminating cyanide-and 1080-induced bait-shyness. Baits containing brodifacoum can also be used very effectively to "mop up" bait-shy populations, but care must be taken to minimize environmental contamination by this persistent compound.

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Comparative effects of brodifacoum on rats and possums

Cited by 21 publications

References 9 publications

Acute toxicity and risk to lizards of rodenticides and herbicides commonly used in New Zealand

Acute toxicity and risk to lizards of rodenticides and herbicides commonly used in New Zealand

The Wake Island Rodent Eradicaation – Part Success, Part Failure, but Wholly Instructive

Learned bait-shyness by possums (Trichosurus vulpecula) towards baits containing cyanide, 1080, cholecalciferol, or brodifacoum

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