Scientists have described as “shocking” the levels of rat poison found in Western Australia’s Masked Owls, warning that the toxic chemicals are killing native wildlife and family pets and calling for an immediate ban on public sales.
The research, led by Associate Professor Rob Davis from Edith Cowan University, tested the livers of Masked Owls collected from the state’s south west and metropolitan Perth. All 16 birds examined were found to have toxic or lethal levels of rat poisons known as second-generation anticoagulant rodenticides (SGARs).
“These poisons are freely available on supermarket and hardware shelves and are used by some commercial pest controllers,” Dr Davis said. “If these levels were true for the entire south west population of Masked Owls, we would not have a population left.”
The study found that all significant exposure was to long-lasting “one-dose kills” poisons, particularly Brodifacoum, with some birds exposed to multiple types. Common brands containing Brodifacoum include Talon, Tomcat II, Ditrac, Ratsak and Surefire.
Dr Davis said the findings likely underestimate the true scale of the problem, as many poisoned owls die unseen in bushland. “Most of the birds we tested were hit by cars or found debilitated by the public. Research shows that owls suffering rodenticide toxicity are more likely to be struck by vehicles,” he said.
The research builds on work by Owl Friendly Margaret River, led by Dr Boyd Wykes, which has shown that Masked Owls have shifted from native prey to feeding on rats and mice living around people. “We have evidence that the major pathway for poisons entering the food chain is wildlife eating dead and dying rodents, as well as directly accessing outdoor bait stations,” Dr Wykes said.
He said the testing, which costs around $300 per bird, has been carried out without government or industry support. “It’s outrageous that these products are not being banned until manufacturers prove they can be made safe for the environment,” Dr Wykes said. “The current government review of rodenticides fails to protect wildlife. Outdoor bait stations and new labels won’t stop the poisoning.”
BirdLife Australia CEO Kate Millar said the findings add to overwhelming evidence that second-generation rat poisons are killing wildlife at unacceptable levels. “The Australian Pesticides and Veterinary Medicines Authority must end the public sale of dangerous SGARs,” she said.
Researchers and conservationists are urging the public to call on Agriculture Minister Senator Murray Watt to intervene and ban the sale of these deadly poisons before more wildlife is lost.
