WARNING – DISTRESSING CONTENT: A common household product sold at supermarkets and hardware stores is devastating Australian wildlife.
The intended target of rat bait is rodents, but newer types of chemicals are killing well beyond their target range.
The study, conducted in Western Australia in 2017-2018, confirmed what many wildlife carers have long suspected - “second generation rodenticides” are building up in the tissue and organs of native birds.
More than 12 months after the study was published, Fast Action Ratsak continues to be sold at Coles, Bunnings and Woolworths.
It is just one of 60 rodent control products registered in Australia that contain a deadly blood thinner called brodifacoum which scientists fear is also affecting native mammals and even humans.
When consumed, the product results in serious internal bleeding which research suggests causes wildlife to be hit by cars, taken by cats or dogs, starve or bleed to death.
PhD candidate Michael Lohr’s research at Edith Cowan University into the tiny boobook owl found more than 72 per cent of carcasses tested had traces of brodifacoum in them.
“A lot of the impacts of this are probably unseen,” he said.
“Birds that are directly killed by rodenticides are probably going to die in a hollow somewhere and never enter the study.”
“It’s a bit grim to think about.”
‘Impossible to make an informed choice’
Yates, the manufacturer of Ratsak, said they are aware of the risk to “non-target species” and provide application directions and cautionary information to consumers.
“This includes instructions on placement of baits, the use of bait stations and appropriate disposal of rodent carcasses,” they said.
Mr Lohr said that despite their visibility on supermarket shelves, he doesn’t want to single Yates out.
He believes labelling across the retail sector makes the purchase of baits a “tricky” issue”.
For instance, Fast Action Ratsak contains brodifacoum, but Double Strength Ratsak lists the milder warfarin as its active ingredient.
“It’s almost impossible to make any sort of informed choice on this when you’re buying them, because most of the brands will make both first and generation products with extremely similar names,” he said.
“They’re right next to each other on the shelf.
“Unless you read the fine print, you have absolutely no idea which chemical it’s going to be.”
Bunnings General Manager of Merchandise, Phil Bishop, said they work with manufacturers to ensure the labelling of poisons is clear.
“As with all of our products, we encourage customers to follow these label instructions and dispose of rodents responsibly,” he said.
Coles did not respond to questions from Yahoo News Australia concerning their sale of the product and how this fits in with any commitment to wildlife.
Woolworths issued a brief statement saying they “comply with standards” set by the Australian Pesticides and Veterinary Medicines Authority (APVMA).
“We advise customers to follow all instructions for use as outlined on the product labelling,” they said.
Threat to wildlife, pets and humans
The APVMA is conducting its first review into second generation anticoagulants, but it remains at the “scoping” stage.
Their website lists “key issues” with the poisons as including labelling, along with the threat to wildlife, pets and humans.
“These chemicals persist in organs of poisoned rodents and present a risk to non-target animals that feed on poisoned animals or carcasses,” it states.
APVMA told Yahoo News Australia “a number of mechanisms” are available to them as part of the review process.
“The APVMA only registers chemical products where the risks can be mitigated through specific application and safety instructions on the product label,” they said.
“It is then the responsibility of state and territory governments to control the use of these products.
“The APVMA expects to consult with Safemeat, Australian Pork Limited (APL), and state and territory environmental, public health, and chemical coordinators in relation to second-generation anti-coagulant rodenticides.”
‘The walking dead’
Mr Lohr explained that rat bait slows rodents down over a number of days, making them easy targets for predators.
“It takes five or six days before the rat starts to feel sick, by which stage they’ve eaten a lethal dose,” he said.
“They’re the walking dead.
“As they get slower, they’re easier prey for non-target predators.”
While traditional baits leave the predator’s system in 35 days, newer rodenticides like brodifacoum stay in their bodies upwards of 217 days, accumulating in the liver and tissue with each rat they eat.
“It’s been misdiagnosed in almost every instance by vets that I’ve talked to,” he said.
“I’ve had all sorts of different causes of death ascribed to boobooks which pretty clearly died of rodenticide poisoning.
“I found one bird that had completely bled out from a little, tiny scratch on the toe.
“So, there was no blood in the bird whatsoever.
“I’ve found other birds through doing dissection that have bled out internally, so their entire body cavity is full of blood.
“I did test two boobooks which were chicks and within 24 hours of leaving the nest they were hit by a car.”
“I collected those chicks and took some blood results.
“Those two livers from those birds came back positive for low levels of two different rodenticides.
“So we do know that they probably are being exposed before they leave the nest, just from food items that they bring back.”
“Seeing dead owls is one thing, but a lot of the impacts from this are probably unseen.”
‘Moving up the food chain’
Australian researchers are turning their attention to whether second generation anticoagulants are making humans sick too.
Scientists suspect it is affecting humans when they eat goanna - a traditional food for Indigenous populations.
“Basically any species which are carnivorous or scavengers are likely to be exposed, because they’re eating dead and dying rodents, or eating things that eat them,” Mr Lohr said.
“These things can keep moving up the food chain.”
Alternative rat control products
Yates told Yahoo News Australia that they offer rat control options that don’t contain second generation rodenticides.
“Yates aims to increase consumer awareness and use of these alternative products.
“We will continue to look for alternative options for consumers.”
Mr Lohr highlighted Ratsak Naturals, sold at Bunnings, as being an alternative poison that he has not found in wildlife, but added there are better options to poison.
“Some of the most effective solutions are just going to be environmental controls,” he said.
“(That includes) cleaning up rubbish around the place, picking up fruits that have dropped on the ground from fruit trees, making sure that your pet food is kept in doors, sealing up any holes in your property - basic things that make your home inhospitable to rodents in the first place.”
The author, Michael Dahlstrom, is a registered wildlife carer in NSW.