Sodium fluoroacetate (1080) is a vertebrate pesticide principally used to control unwanted introduced mammals in New Zealand and Australia. For 1080, over 260 publications during the last ten years supplement a body of scientific information regarding its mode of action, natural occurrence, toxicology, antidotes, metabolism, and fate in the environment. Multi-year studies have explored long-term outcomes for multiple native bird species. Numerous reviews on community attitudes stimulated by the Predator Free New Zealand (PFNZ) 2050 campaign conclude that 1080 use for conservation remains controversial. Further effort is needed to increase target specificity, avoid game species, and employ approaches with the highest public acceptance, including hunting, trapping, and species-specific toxins. Greater acceptance of the large-scale use of any pest control is likely when long-term goals and strategies for ecosystem recovery employ toxins as one-off treatments for eradicating pests versus continued applications.

Possum control in New Zealand is dependent on the use of sodium monofluoroacetate (1080) and cyanide. Although 1080 is highly effective, its use is restricted to government staff. Cyanide is available for a wider group of licensed operators, but cyanide "shyness" reduces its effectiveness. An acute toxicity programme has been set up to identify non-anticoagulant toxins that could be used safely by farmers. Dose-ranging studies showed that possums are susceptible to cholecalciferol, calciferol, gliftor, alpha-chloralose, and nicotine, but not to bromethalin. As lethal doses for these toxins have been ascertained, which of them are likely to be cost-effective and safe alternatives to 1080 now needs to be established. Bait palatability and field studies will then be undertaken with the most promising candidates.

PAPP is short for para-aminopropiophenone and is a new vertebrate pesticide. It is a compound with the formula C9H11NO, it is comparative humane, has low secondary poisoning risk, and has an antidote. PAPP was originally trialed in the 1960s as an antidote for human radiation and cyanide poisoning. In the USA, it has been investigated as a tool for coyote control and was found to be specifically much more toxic to carnivores than to birds and humans. In Australia, it will be used for field control of foxes, wild dogs, and feral cats. In New Zealand, PAPP was registered in 2011 for the control of stoats and feral cats, following the completion of pen and field trials and submission of extensive dossiers covering its effectiveness as a pest control agent and on its ecotoxicology, toxicology, and metabolism.

Norbormide is a rat specific toxicant. It causes vasoconstriction of small arteries and vasodilation of large arteries in rats, which results in a rapid fall in blood pressure and death from heart failure. It is an extraordinary compound in that it is only toxic to rats. The lack of toxicity of this compound to birds and other mammals is unique. It was originally researched in the 1960s and initially marketed in the USA. Problems with taste aversion slowed its continued use and sales it and was largely forgotten when anticoagulant rodenticides became more effective and popular. Following the emergence of anticoagulant resistance in some populations of rodents, residues of the second-generation anticoagulants in wildlife and concerns regarding humaneness, interest in non-anticoagulants, such as norbormide, has revived. Research has been conducted to help identify and understand a formulation of norbormide which is palatable, effective, and fast acting in rats. Further research is underway to determine methods for large scale synthesis of an improved form of norbormide. Field trials are planned in 2018/19. The ability to target rats with no risk to non-target species presents considerable advantages in many settings and warrants further investment and completion of the current scale-up phase of research and development.

Rodenticides such as brodifacoum are more potent than first-generation anticoagulants. However, their field, farm, and outdoor use in urban settings have been linked to bioaccumulation and non-target impacts for more than three decades. Product development strategies focused on baits that yield good control of pests without residue risks to wildlife are few. To fill this gap, a bait containing a combination of diphacinone at 0.005% and cholecalciferol at 0.06% (D+C bait) has been developed as a multispecies bait for NZ use, that is effective at killing rodents and also possums (Trichosurus vulpecula), which are resistant to the toxin effects of first-generation anticoagulants. This bait was approved by the NZ Environmental Protection Agency and the product registered by the NZ Ministry of Primary Industries in 2019. A new bait is being considered with a lower dose of cholecalciferol. A bait containing half or a quarter of the loading concentration of cholecalciferol would have an even better safety profile for rodent control alone. Cage trials indicate that cholecalciferol at 0.03% with diphacinone 0.005% is as effective as brodifacoum as a single exposure bait. Amounts of cholecalciferol as low as 0.015% significantly improve the effectiveness of diphacinone.

Rodent eradication on islands has transitioned over 30 years in New Zealand through stages of initial scepticism, to early accidental and experimental successes, and now to the current bold large-scale aerial applications over increasingly large and complex island ecosystems. Starting in the 1970s and 1980s, gaining momentum in the 1990s, and continuing to the present day, islands once occupied by rodents are now being reclaimed. Until the mid 1980s, very few islands were entirely free of animal pests. Rodent eradication on islands, using bait in stations and baits applied from the air, has been spectacularly successful. To date, more than 90 islands around New Zealand have been cleared of rodents, and brodifacoum use has had an obvious benefit on valuable island ecosystems. The tactical use of toxic bait to protect island populations of indigenous birds, reptiles, and invertebrates endangered by rats and mice continues to be refined to enable larger and more complex islands to be cleared of rodents. New bait types that are especially attractive to mice as well as rats, long-life baits, new toxins, and tunnel delivery systems will augment existing bait types to aid future eradication programmes and help prevent re-invasions. New developments will need to be ethically and socially acceptable and demonstrate clear advantages in non-target impact as well as efficacy in achieving eradication. These endeavours are part of global efforts to eradicate invasives and manage islands to protect native birds and other important fauna and flora.

To determine the risk of secondary poisoning for animals preying on sub-lethally poisoned brushtail possums, captive possums were treated with near-lethal doses of sodium monofluoroacetate (1080) or brodifacoum, and toxicant concentrations in blood and tissue were monitored over time. Sodium monofluoroacetate was rapidly eliminated from the blood (within three days). Brodifacoum was retained in the liver and, to a lesser extent, the muscle of possums for eight months after dosing. To determine the potential risk for animals scavenging on the carcasses of possums poisoned with cholecalciferol, cats were fed poisoned carcasses for six days. No changes in behavior, appetite, or body weight were observed. Serum calcium concentrations increased slightly, but remained within the normal range for cats.

The use of infrared-flash camera traps has increased dramatically over the past ten years particularly for capturerecapture population studies of distinctly-marked species. However, to use capture-recapture with the more inconspicuous species, high-quality colour imaging (and therefore white flash) is required. A potential problem with white flash is that it may negatively affect behaviour, in this case at bait stations, therefore causing results that do not truly represent possum activity. Possums were used in this study to compare two different types of camera trap: infrared and white flash. Camera traps were placed to take images of possums visiting bait stations, and the number of possum visits was used to determine if white-flash cameras gave different results to infrared-flash cameras. The white-flash cameras had slightly higher possum visits than infrared-flash cameras but the difference was not significant (P=0.437). Over time, the number of possum events (P=0.62) and the amount of time possums spent at the stations did not differ significantly (P=0.81). There was also no difference in the amount of bait taken by possums at white flash compared to infrared stations (P=0.61). Results show possums are not likely to be affected by white-flash cameras compared to infrared-flash cameras. This study therefore showed that there is unlikely to be any behavioural disadvantage in using white flash over infrared, allowing white-flash cameras to be investigated for their potential in identifying individual possums, and as a monitoring tool in control operations.

To improve feral cat control we developed a dry pelleted toxic bait and evaluated the potential of lures. A polymer fish meal bait was preferred by cats from a range of bait types tested. L-alanine further increased bait acceptance by cats in pen trials and catnip may have the potential to increase field acceptance and target specificity. An oral LD90 of 0.38 mg/kg was established for sodium monofluoroacetate (1080) in feral cats voluntarily eating surface-loaded baits. Acute toxicity to cats of warfarin, cholecalciferol, and gliftor was tested. However, because the cat proved highly sensitive to 1080, we recommend its use at a dose of 2 mg per cat bait. In preliminary field trials of bait acceptance using non-toxic polymer bait (without flavours or attractants), marked with the plasma marker iophenoxic acid, 50% of 39 cats caught within 3 weeks of laying the baits were marked. Subsequently polymer bait, surface coated with 1080 was used in the successful eradication of feral cats from Matakohe Island (37 ha), Whangarei Harbour, New ZeaJand.

There is a need in New Zealand for a new, more advanced generation of toxins to minimize the impact of invasive animals. A new pest control agent, para-aminopropiophenone (PAPP), represents a lead candidate presently undergoing registration for the humane control of stoats and feral cats. It exhibits low toxicity to most bird species, no secondary poisoning risk, and has a simple and highly effective antidote. PAPP induces methemoglobinemia (MtHb), which acts to prevent oxygen from binding to red blood cells. This reduces oxygen supply to the brain, causing animals to become lethargic, sleepy, and unconscious prior to eventual death in 1 to 2 hours. Despite such promise, to date no previous study has comprehensively examined the effect of modifying the structure of PAPP on MtHb induction. Using PAPP as a platform, this paper describes the design, synthesis, and bioevaluation of PAPP-like red blood cell toxins. The impacts of introducing groups of varying electronic nature at different positions on the PAPP molecule are presently being evaluated. Analogues are synthesized and their MtHb-inducing properties determined using an in vitro assay to establish a formal structure-activity profile. In vivo evaluation in rats is used to assess both their acute toxicity and humaneness of potential candidates. Structure-activity profiles are discussed with the objective of optimizing the bioavailability and potency of PAPP-like compounds to target, high priority pests, particularly rodents.