The dangers of SGARs
Second-generation anticoagulants, commonly abbreviated as ‘SGARs’, have long been used as potent poisons to kill unwanted rat and mouse populations. Their use, however, comes with significant risks to non-target species, including wildlife and companion animals. Concerns over the safety and environmental impact of SGARs have grown in recent years, prompting a need for stricter regulations and the exploration of alternative methods. In this blog, we will delve into the use of SGARs, the potential risks they pose to non-target species, and the available alternatives. We will also discuss the products containing SGARs that are currently used in Australia and how animal rights advocates can take action today.
What are SGARs?
SGARs are a group of highly toxic poisons used to kill unwanted rodent populations. They are more potent and longer-lasting than their first-generation counterparts (FGARs), which have fallen out of favour due to safety and environmental concerns. SGARs work by interfering with the blood clotting mechanism, leading to internal bleeding and eventual death in their victims. However, non-target species, such as birds of prey and other wildlife, are also at risk if they consume toxic rodents or bait.
Who is at risk from SGARS?
In Australia, various bird species, including owls, eagles, and magpies, as well as mammals like quolls and possums, are particularly vulnerable. These animals are at an increased risk because they prey upon the intended victims of SGARs: rats and mice. Furthermore, even companion animals face danger if they come into contact with this toxic substance. Animals affected by SGAR poisoning often face severe symptoms, requiring costly emergency veterinary treatments. Due to the poor prognosis and suffering associated with SGAR poisoning, euthanasia is often the unfortunate outcome.
What are the problems with SGARs?
SGARs have a notorious reputation for causing poor animal welfare outcomes. Victims of SGAR poisoning suffer from internal and external bleeding, leading to a slow and painful death that can last for several days. This delayed effect allows poisoned animals to travel considerable distances, increasing the risk to other animals that may scavenge their bodies. Experts have highlighted that SGARs are “capable of producing severe pain”, with anticoagulants ranking among the toxins causing the most severe and prolonged impacts on animal welfare. Unlike earlier anticoagulants, a single dose of an SGAR is often enough to be lethal.
Furthermore, as is the case with many toxins, such as 1080 poison, the victims of SGARs are not limited to their intended targets. These poisons pose a secondary threat to animals that consume them, leading to primary, secondary, and even tertiary poisoning. Studies conducted worldwide have found alarming rates of SGARs present in bird species, with over 60% of sampled birds showing traces of these poisons. In Australia, the figures are even higher, with recent studies detecting SGARs in the bodies of more than 80% of sampled birds. This highlights the urgent need for action to prevent further harm to wildlife.
Which SGAR products are registered and used in Australia?
There are currently five SGARs registered for use in Australia: brodifacoum, bromadiolone, difethialone, difenacoum and flocoumafen. Though the Federal regulator of pesticides approved these chemicals, it warns that these poisons “pose a higher risk of secondary poisoning” than others.
Brodifacoum
Brodifacoum was developed in the mid-1970s and causes concern because it persists in both target and non-target victims. It causes prolonged suffering, with possums taking more than 3 weeks to die after ingesting a brodifacoum bait.
There are a range of products registered in Australia that contain bromadiolone. These include:
‘Mortein Mice/Rat Kill Professional’
‘Pest Defence’
‘Raticide’
‘Ratshot Red’
‘Rodenthor’
‘Surefire’
‘Tomcat II’
‘Top Cat’.
It takes rats between 3-14 days and mice between 4-18 days to die from brodifacoum poisoning.
Image: brodifacoum baits for sale in Australia (source)
Bromadiolone
Bromadiolone was patented in 1967 to kill rats and other rodents. Bromadiolone poisoning leads to severe bleeding in different organs and tissues, resulting in severe symptoms. Research shows that bromadiolone can persist for up to 135 days in poisoned animals and has been found in the livers of birds of prey.
During the recent “mouse plague” in NSW, the state government sought permission to grant farmers free access to 5,000 litres of bromadiolone. As critics explained, this amount is enough to poison 95 tonnes of grain. Thankfully, the Federal regulator rejected the emergency permit application for bromadiolone made by the NSW Department of Primary Industries. The decision was based on concerns about its impact on the environment, including the risk of secondary poisoning to birds, fish, and reptiles. Additionally, the toxicity of the chemical to humans who consume predatory freshwater fish or reptiles from treated areas was also a factor.
Despite this, there are a range of products registered in Australia that contain bromadiolone, including:
‘Alley Cat’
‘Bromakil’
‘Bromakil Rat Drink’
‘Just One Bite’
‘Generation Green’
‘MouseOff’
‘Rat Stop’
‘TomCat’.
It takes rats between 2-16 days and mice between 3-19 days to die from bromadiolone poisoning.
Image: bromadiolone baits for sale in Australia (source)
Difethialone
Difethialone was developed in France and first applied in 1986. Although difethialone belongs to a different chemical family than other second-generation rodenticides, it works in the same way by acting as an anticoagulant. This prevents blood from clotting, resulting in death from internal or external bleeding. Compared to other SGARs, difethialone is known to be more toxic to birds and fish.
There are two products registered in Australia that contain difethialone:
‘Generation Blue’
‘Rodilon Pro’.
It takes rats between 4-13 days and mice between 4-22 days to die from difethialone poisoning.
Image: difethialone baits for sale in Australia (source)
Difenacoum
Difenacoum was first marketed in 1975, making it one of the earliest commercially available SGARs. Though it is the least potent SGAR, when a rodent eats a difenacoum bait, it still stops an important enzyme and disrupts the recycling of vitamin K. This leads to a decrease in blood-clotting substances, causing bleeding, and eventually death.
There are a range of products registered in Australia that contain difenacoum, including:
‘Atlas’
‘Cougar’
‘Patrol’
‘Ratsak’
‘Ratshot’
‘The Big Cheese’
‘Time’s Up’.
It takes rats between 4-13 days and mice between 4-22 days to die from difenacoum poisoning.
Image: difenacoum baits for sale in Australia (source)
Flocoumafen
Flocoumafen was first synthesised in 1984. Although flocoumafen is similar in chemical structure to older anticoagulants, like warfarin and coumatetralyl, it is classified as an SGAR because it is stronger and more effective at killing rodents who have developed resistance to other chemicals.
There are two products registered in Australia that contain flocoumafen:
‘Storm’
‘Stratagem’.
It takes rats between 3-11 days and mice between 4-19 days to die from flocoumafen poisoning.
Image: flocoumafen baits for sale in Australia (source)
Taking Action Against SGARs
Recognising the potential threat to wildlife and increasing public interest, progressive councils are increasingly acknowledging and acting on concerns surrounding the use of SGARs. In February 2023, the Victorian Government's Scientific Advisory Committee officially recommended recognising the poisoning of wildlife by SGARs as a potentially threatening process for native Australian species.
By raising awareness, educating others, and advocating for stricter regulations and alternatives, we can protect both wildlife and our beloved companion animals from the dangers posed by SGARs.
How can we work together to ban SGARs?
The continued use of SGARs carries grave consequences for non-target species, including wildlife and companion animals. The potent and long-lasting nature of these poisons poses a serious threat to animal welfare, causing internal bleeding, prolonged suffering, and a slow death. Moreover, secondary poisoning places additional species at risk when they consume the carcasses of toxic rodents.
With studies showing alarming levels of SGARs in bird populations, urgent action is needed to protect wildlife from further harm. Fortunately, progressive councils and scientific advisory committees have started to recognise the urgency of addressing this issue.
As concerned advocates for animal rights, it is crucial to support initiatives that improve protections for wildlife. We strongly recommend you support BirdLife's campaign to ban SGARs. By supporting efforts like these, we can make a difference in advocating for stricter regulations and safer alternatives.
Page updated 12 April 2024