Commonly used toxic products used to kill rodents are harming native animals in increasing numbers, according to wildlife experts.
Months of higher than expected rainfall in Australia's east over the past few years has seen a rise in the use of poisonous baits, many of which end up in the bodies of animals such as owls, quolls, goannas and possums.
It has prompted the ACT government to announce it will investigate whether the products need to be more tightly regulated to mitigate their impact on the natural environment.
In the meantime, people are being urged to consider alternatives when attempting to rid their homes and businesses of vermin.
'A horrible way to go'
Wildlife ACT volunteer Corin Pennock sees the impacts of poisonous baits regularly.
Tasked with caring for very young possum joeys who require round-the-clock feeding, she routinely adopts those whose parents have died from ingesting bait.
Sometimes, the joeys themselves show signs of having been poisoned, by taking in the chemicals via their mother's milk.
"They're very pale and you can often see blood pooling in the pads of their feet," Ms Pennock said.
"It's a very horrible way to go, it's very slow."
Carers treat poisoned animals with vitamin K, but it's not always successful, and some eventually die.
She said it was difficult to see them suffering from something that was preventable.
"It is very hard to see them without their mum, they should be with their mum all the time — we're only a substitute," Ms Pennock said.
Highly toxic baits 'really problematic' for wildlife
Melissa Snape, a senior ecologist within the ACT government's urban biodiversity team, said in more recent years, stronger poisons had become more popular.
She said while these products were more effective at killing rodents, they had serious longer-term consequences.
"There's two different types of anticoagulant poisons, first generation and second generation — the first generation ones didn't hang around in the body's tissue for as long, so they weren't as impactful ... but they also didn't work as well," she said.
"Now we're seeing a shift towards what's called second generation anticoagulants, and they're really problematic."
She said the more rodents killed by bait an animal consumed, the more poison it accumulated in its system, which could eventually lead to a lethal dose.
Threatened and endangered species are among those to have been found with the toxins in their systems.
"Not only does the mouse eat it, but it hangs around in the tissues of the mouse for a really long time," Dr Snape said.
"Which means that if something like an owl or a goanna or even a quoll was to eat that mouse, it then passes up the food chain and it actually hangs around in the bodies of those animals for a really long time."
Research has shown the toxic chemicals are affecting a huge percentage of native wildlife across Australia.
"A study that we've been doing in the ACT, but also across Australia, has shown that of the 83 samples that we tested, more than 80 per cent of wildlife were being impacted," Dr Snape said.
Push to correct Australia's 'sorry history' with pest management
ACT Environment Minister Rebecca Vassarotti said she shared the concerns of ecologists, and would be tasking the Legislative Assembly's science committee with investigating whether the products should be restricted.
Some countries have introduced bans on the products, and while Australia has yet to follow suit, the national regulator is looking into whether a similar ban should be introduced.
Ms Vassarotti said it might be necessary to act more quickly in the ACT.
"We are really quite keen to look at what regulatory approaches we might need to put in place to ensure we're doing everything we can to protect our native wildlife," Ms Vassarotti said.
"We are quite aware that Australia does have quite sorry history when it comes to some of the unintended consequences of how we manage pests."
She said it was important in striking a balance when it came to pests, while also mitigating the use of harmful chemicals.
"We're not going to do anything that means that we can't effectively manage pests in the in the urban and the rural environment, but particularly when we see that there are alternatives, we're really quite keen to look at what regulatory approaches that we might need to put in place," she said.
Ms Pennock welcomed the news that steps might be taken to remove harmful chemicals from the environment.
"It is very exciting," she said.
"As a carer myself, and I know that many of my other possum and bird carers, we find it very hard seeing these animals come in and we can't always save them.
"It would be really good if there was a change."
Dr Snape encouraged people to avoid rat bait altogether when trying to control rodents, and choose snap-traps or electric traps instead.
But she said if rat bait was the preferred method, the best products were those that are salt-based, such as Ratsak Naturals.
She also said that ensuring any food or animal feed was kept out of reach and in sealed packaging would help to prevent rodents.
