Queensland Rat Poisoning: Crisis on the Australian Food Chain

Rat poison crisis in Queensland: SGARs, a ‘silent killer’, are decimating native wildlife, including owls and quolls. Calls grow to restrict public sale of potent rodenticides.

Conservation groups, veterinarians, and scientists across Queensland are sounding the alarm over the widespread and increasing issue of native wildlife—including owls, birds of prey, and marsupials—being poisoned by common rat baits.

The quiet crisis, often referred to as secondary poisoning, is raising serious questions about the free availability of highly potent rodenticides to the general public.

The Lethal Link: SGARs in the Ecosystem

The core of the problem lies with Second-Generation Anticoagulant Rodenticides (SGARs). These powerful poisons are designed to be extremely effective, often requiring only a single feed to kill a rodent. Crucially, they remain in the rodent’s body and liver for an extended period—often days or even weeks—before or after death.

When native carnivores or scavengers—such as Powerful Owls, Tawny Frogmouths, Kookaburras, and even Quolls, prey on the sick or dead rodents, the poison passes up the food chain.

Recent studies from across Australia highlight the alarming extent of exposure:

• Widespread Exposure: Research on various Australian predators, including owls and frogmouths, shows extremely high rates of exposure to these poisons, with one study indicating SGARs were detected in over 90% of tested nocturnal predatory birds.
• Lethal Accumulation: Even if a single poisoned mouse doesn’t kill a predator, the continuous consumption of exposed prey leads to a dangerous buildup of the toxin in the predator’s liver, causing slow, painful internal bleeding and eventual death.
• Impact on Threatened Species: Experts warn that even sub-lethal doses can weaken an animal, making it more vulnerable to disease or predation, potentially accelerating the decline of already threatened species like the spotted-tailed quoll.

The Human Factor and Calls for Action

The widespread nature of this poisoning is directly attributed to the ease with which SGARs can be purchased at supermarkets, hardware stores, and garden centres by homeowners and businesses.

“When you put out a rat bait, you are not just targeting the rodent; you are inadvertently putting poison into the broader food web,” said a local wildlife rescuer. “We see the consequences firsthand—a slow, painful death for a beautiful native bird or possum.”

Conservationists are urgently calling on the Australian Pesticides and Veterinary Medicines Authority (APVMA) to follow the lead of jurisdictions in North America and Europe by imposing stricter controls on SGARs. Key proposals include:

1. Restricting Sale: Limiting the sale of SGARs to licensed professional pest controllers only.
2. Banning Outdoor Use: Prohibiting the use of these potent chemicals outdoors in domestic and urban environments, where the risk to non-target animals is highest.
3. Promoting Alternatives: Encouraging the public to use non-poisonous control methods like exclusion (sealing entry points) and humane trapping, or to switch to less persistent First-Generation Anticoagulant Rodenticides (FGARs).

As Queensland grapples with pest control in urban and agricultural settings, the growing toll on its unique and irreplaceable native fauna necessitates an immediate review of current rodenticide regulations to prevent further catastrophic damage to the state’s wildlife populations.