This is a final version submitted for publication. Minor editorial changes may have subsequently been made.
Many rural Australians have a dread of rabbits. If they see one or two on their property they have visions of hoards of rabbits teeming over the land, eating all available vegetation, undermining trees and bushes, and destroying everything in sight. Indeed rabbits have been a major problem in many agricultural areas in the past and efforts to eradicate them have included the introduction of the viruses Myxomatosis in 1950 and calicivirus since 1995.
Although calicivirus has been successful in significantly reducing rabbit numbers, some survive and landholders are now ever vigilant of rabbits for fear they may again reach plague proportions. Their efforts in this regard are aided in NSW by the Livestock Health and Pest Authorities (LHPA) in areas where it deems rabbits are too numerous. The LHPA uses calicivirus, poisons such as 1080 and pindone, and habitat destruction, in conjunction with councils and landholders.
As a regulatory agency concerned with the health of livestock, the LHPA is "committed to safeguarding agricultural production from the biosecurity risks posed by disease and pests". However, its domain is not restricted to agricultural areas and it has been active in semi-urban and coastal areas throughout the state. Most recently the LHPA has been active in coastal areas of southern NSW, promoting the use of pindone to kill rabbits and training local landholders to use pindone-baits.
Pindone is not a target-specific poison and has the potential to kill other animals including humans, pets and wildlife. It is used in urban-fringe areas, and places where there are concentrations of small landholders, in preference to the poison 1080 because its slower killing time, and the availability of an antidote, make it less dangerous to use around humans and pets. However these factors will not prevent the poisoning of wildlife and it is for this reason that in some Australian states, including NSW, pindone is not supposed to be used where significant native wildlife populations occur.
The far south coast of NSW is a rural area supporting a variety of agricultural production and many small landholdings with an intimate mixture of open fields, bush blocks, lakes, swampy areas and National Parks. This coastal zone includes a range of fauna habitats and a wide variety of native species co-existing in close proximity. There is a surprising number of threatened species that are either known or predicted to be in the area, including several species of owl (including the Barking Owl), the Spotted-tailed Quoll, the Little Eagle, the Southern Brown Bandicoot, and the Long-nosed Potoroo.
Last year the Eurobodalla Shire Council in coordination with the LHPA undertook a program of pindone-baiting of rabbits on council land in the area. The Council claims this is in response to complaints by residents about rabbits digging in their gardens and eating their plants. The Council did not undertake any assessment of the risk pindone poses to native wildlife in the area but instead relied on the advice of the LHPA, which in this case recommended the use of pindone and also coordinated landholders in some areas to conduct simultaneous poisoning on their properties.
Every program of pest eradication by poison has to take into account the effect it will have on both target and non-target species. To do this it has to take account of the effects, and the risks, of both primary and secondary poisoning of animals. Primary poisoning occurs when target and non-target animals consume baits; secondary poisoning occurs when predators eat sick animals that have been poisoned or scavengers eat the carcasses of poisoned animals.
A program of feral animal control that is neither cruel nor careless requires that target animals do not have a slow, painful death and that poisoning is confined to target species. The use of pindone baits does not meet either criteria.
Pindone is an anticoagulant that kills by interfering with blood clotting, causing fatal haemorrhages. According to Trudy Sharp and Glen Saunders, scientists from the NSW Department of Primary Industries, who prepared a Model Code of Practice for the humane control of rabbits for the federal government, it takes around 10 to 14 days for rabbits to die following initial ingestion of pindone. During that time the animals bleed from the nose, mouth, eyes and anus, and pain from bleeding in internal organs, muscles and joints lasts for several days before they die. They conclude: "Because anticoagulant poisons take several days to kill, during which time they cause distress, disability and/or pain, they are considered inhumane."
The assessment of what is and what is not a cruel or inhumane way to treat animals is a contentious issue. The institution with the most influence and established moral standing in Australia on matters relating to animal welfare is the RSPCA. On its website the RSPCA has a page titled, "What is the most humane way to control rabbits". Shooting and cage trapping are recommended as the most humane methods of control while 1080 is considered inhumane. In regard to pindone the RSPCA is unequivocal in its criticism and says that it does not consider pindone "an acceptable control method as affected rabbits take several days to die".
Whereas the question of cruelty is focused largely on rabbits the question of carelessness centres on the risk of collateral damage − the killing of non-target species. Common wildlife at risk of poisoning by pindone in the coastal area of southern NSW includes swamp wallabies, redneck wallabies, kangaroos, possums, antechinus, bandicoots, owls and eagles.
In October the ABC reported that over 400 birds including kelp gulls, giant petrels and black ducks had been killed on Macquarie Island after being exposed to another anticoagulant poison, brodifocoum, used to eradicate rabbits and rodents on the island.
There are few studies of the toxicity of pindone to Australian native fauna. According to a 2002 survey of the literature by the National Registration Authority for Agricultural and Veterinary Chemicals (NRA – now the APVMA) the available information "indicates that a number of native species (macropods [kangaroos and wallabies], bandicoots, dasyurids, raptors and a range of granivorous birds) are likely to share the high sensitivity of rabbits to pindone".
Although the 2002 NRA review found that "pindone poses a manageable risk to non-target species", throughout the report there are constant references to the limited availability of scientific data and, with regard to the persistency of pindone residues, it admitted that its findings were "very tentative".
According to the NRA review, laboratory studies have found that owls can be poisoned by eating pindone-contaminated mice carcasses and that "raptors appear to share the high sensitivity [to pindone] of rabbits, based on results for wedge-tailed eagles and brown goshawks".
The LHPA response to the risk of secondary poisoning is an unproven assertion that this risk is very small because the sick rabbits go back to their burrows to die, an assertion that the LHPA does not seem to believe in since it recommends that the most effective way to poison rabbits is with "a series of smaller doses over a period of 4 to 12 days" rather than one large dose. This means they expect the rabbits to be up and about for up to 12 days after taking the first bait, plenty of time for predators to find them.
Pindone was declared ineligible for registration in the US and has never been registered in the UK. However in New Zealand it is registered and widely used for killing rabbits and has even been deliberately used to kill possums and wallabies, which are considered to be pests.
In Australia, the LHPA can actually require landholders to lay pindone baits in order to control rabbits. Before using LHPA supplied baits the landholder must sign a legally-binding indemnity form for every property where they intend to lay the baits. The form states that the landholder indemnifies the LHPA and all its employees against any actions, proceedings, claims, demands, costs and expenses that result from injury to any person, loss of any animal or any other loss.
Pesticide Control (Pindone Products) Order 2010, gazetted in August 2010, enables landholders to use 1080 and pindone after attending a short three-hour course. By the end of October some 200 people had been trained, many of whom own small lifestyle blocks near or including wildlife habitat.
Although it is illegal to use pindone without doing the short course a curious anomaly remains whereby anyone can still purchase ready-mixed pindone baits over the counter of hardware and produce stores without showing credentials. While this anomaly remains pindone can easily and unknowingly be used illegally. A maximum $60,000 penalty is prescribed for non-compliance with the new regulation.
LHPA authorised control officers are culpable if they knowingly organise or coordinate pindone-baiting campaigns in areas where threatened species are likely to be at risk. An LHPA officer told those attending a short course at Moruya that the risk assessment required by landholders before pindone baits are laid "can be just a good hard think" although in some sensitive areas the LHPA will undertake the risk assessment on behalf of landowners.
According to a policy officer from the NSW Department of Environment, Climate Change and Water, if a landowner assesses the risk to wildlife is low and uses a mesh canopy then they will be able to cite that in their defence but there is no guarantee that if, say kangaroos are killed by pindone-baits the landowner has laid, they won't be prosecuted. When the issue of landholder liability was raised at the Moruya short course, landholders were reassured that the Department is very unlikely to prosecute any landowner in the event of wildlife deaths.
More information and references: Pindone Rabbit Baiting — Cruel and Careless