In April 2019, several news articles from around the world reported that the Australian government had a plan to cull millions of feral cats using poisoned sausages dropped by air. CBS News published an article with the headline "Australia is Trying to Kill Millions of Stray Cats by Airdropping Poisoned Sausages," which went on to report that:
"The Australian government wants to kill two million feral cats by next year — and it wants to do it by airdropping poisonous sausages. There are currently an estimated 2 to 6 million free-roaming cats across the country, and officials say they are threatening native wildlife populations."
On 29 April, the UK Independent published an article with the headline "Australia Plans to Kill Millions of Feral Cats by Airdropping Sausages Laced With Poison" and on 26 April CNN reported that:
"Australia is at war — with feral cats. By 2020, the government wants to kill two million free roaming cats, a large chunk of the total feral cat population, which is estimated to be between 2 and 6 million."
We received multiple inquiries from readers about the accuracy of these reports, and in particular about the claim that the primary or exclusive culling method was to be sausages laced with poison. The Australian government has indeed begun an initiative aimed at culling millions of feral cats, which they have described as "one of the greatest threats to Australia’s land-based mammals" and blamed for driving some species into extinction.
However, the culling project was first announced in 2015 and was already well underway when reports happened to emerge about it in April 2019.
In 2015, Australia's government launched the Threatened Species Strategy. One of its four key strategies related to feral cats, and the policy outlined a target of culling 2 million such cats by the year 2020 and eradicating feral cats entirely from five of Australia's islands, among other goals. A government report launching the initiative stated that:
"The scientific evidence is unequivocal that feral cats are one of the greatest threats to Australia’s land-based mammals. They have been a major contributor to the extinction of at least 27 mammals since they were first introduced to Australia. Today, they imperil at least 142 species or more than one third of our threatened mammals, reptiles, frogs and birds. As an extinction driver for so many of our native animals, and a threat that has been relatively neglected in the past, tackling the threat of feral cats is the highest priority of this Action Plan."
By the end of 2016, researchers from RMIT University in Melbourne reported that an estimated 211,000 feral cats had been culled as part of the initiative, but also estimated that 83 percent of those animals had been shot, rather than poisoned. More up-to-date figures were not included in the progress report relating to the period ending in December 2017.
In order to achieve the goal of eradicating 2 million feral cats, the first action listed by the government was the "development and deployment of Curiosity, the new humane feral cat bait." Australia's Department of Environment and Energy had spent years developing and testing Curiosity, a new form of sausage bait that, according to the government, is less likely than existing baits to be consumed by other animals:
The Curiosity bait for feral cats has been a long-term $5.1 million project to develop a humane, broad-scale toxic bait to control feral cats in conservation areas. The Curiosity bait for feral cats comprises a small meat-based sausage containing a small hard plastic pellet encapsulating a humane toxin. Cats do not have molar teeth and tend to chew their food less so they may swallow portions of the sausage including the pellet. Most Australian native animals nibble and chew their food and are likely to reject the pellet. The pellet is designed to dissolve in the cat’s stomach and deliver a rapid dose of the toxin.
The Curiosity bait for feral cats uses a new humane toxin called para-aminopropiophenone, or PAPP, which is considered best-practice world-wide. In brief, the toxicant, PAPP, converts the animal’s red blood cells to a form that cannot carry oxygen, causing death through oxygen starvation to the brain and other vital organs. It is considered to be humane and death takes minutes to hours. The RSPCA [Royal Society for the Prevention of Cruelty to Animals] have indicated that PAPP is a clear improvement in humaneness over previous toxins. The mode of action means that secondary poisoning of any other animals from consuming a carcass of a cat that ate a Curiosity bait containing PAPP is much less likely than when using previously employed toxins.
(Although the excerpt serves to explain the Australian government's reasoning in favoring the Curiosity bait, it does contain a factual error: cats do have molar teeth, albeit only two, and they are used for tearing flesh rather than grinding, so the overall claim that cats tend to chew less and swallow more readily than other animals, appears to stand).
In government-commissioned field trials of Curiosity, the bait has been distributed on the ground in target areas using both aircraft and ground vehicles.
As of April 2019, the Australian Pesticides and Veterinary Medicines Authority was still assessing the PAPP variant of Curiosity. But the national government appeared confident it would be registered as a pest-control product, because in November 2018 the Department of the Environment and Energy solicited applications for a commercial partner to manufacture and sell the bait.
Although no significant developments in relation to the culling program took place in the spring of 2019, interest in the initiative was revived by a 25 April article published by The New York Times, which bore the headline "Australia is Deadly Serious About Killing Millions of Cats," and mentioned the existing use of another kind of sausage-borne cat bait containing the active ingredient sodium fluoroacetate, known as "1080."
In February 2019, a group of Australian scientists questioned the basis of the government's target of culling 2 million feral cats by 2020, in part saying the government had not given a clear metric or scientific rationale for that number; had failed to indicate how or whether the cull would lower the overall population of feral cats (given the rapid rates at which they reproduce) and also increase the populations of endangered species; and because estimates vary widely over how many feral cats actually live in Australia. In a paper published in the journal Conservation Letters, the researchers wrote:
"The focus on killing cats runs the risk of distracting attention away from other threats to biodiversity, most prominent of which is widespread, ongoing habitat loss, which has been largely overlooked in the Threatened Species Strategy. The culling target is a highly visible symbol of a broader campaign around feral cat research and management in Australia, rather than a direct indicator of conservation action and success. We are concerned that progress toward the 2 million target could be misinterpreted as progress toward conserving threatened species, when the link between the two is not clear."