Eradicating feral cats – a possible alternative

There has been a huge amount of media attention recently about the number of feral cats in Australia and the need to significantly reduce their numbers. Tim Doherty provided a summary of some of the recent media here, so there is no need to repost them all.

What is clear from these articles is that Australian scientists are acutely aware of the problem but there is no consistent methodology being applied to deal with the issue. Methodologies currently being used include trapping, shooting and fencing but when used to manage large areas these techniques are often limited by the high costs. The distribution of poison baits is another method being trialed as a lower cost alternative, however, scientists must first address the hazard that surface laid baits may present to non-target species.In a recent paper by Dundas et al (2014) 99% of baits monitored by cameras were taken by non-target species, with the majority taken before or on the first night of deployment, and 95% of baits had been taken within 7 days.

In WA, scientists are working to develop Eradicat® which is a bait suitable for application in areas where native wildlife have a high tolerance to the poison, sodium monofluoroacetate (1080). As a result, this bait is generally unsuitable for use in areas outside of WA, including eastern Australia. The Australian Government therefore funded the development of an alternative bait for feral cat control that is based on Eradicat®. This new bait, Curiosity®, exploits differences in feeding behaviour between feral cats and non-target species by presenting the toxicant, para-aminopropiophenone (PAPP) in an encapsulated pellet.

The Curiosity® bait for feral cats comprises a small meat-based sausage containing a small hard plastic pellet encapsulating the toxin. Cats do not have molar teeth and do not chew their food so they will reliably swallow portions of the sausage including the pellet. Most of our native animals nibble and chew their food so will reject the pellet. The pellet is designed to dissolve in the cat’s stomach and deliver a rapid dose of a humane toxin.

Both of these baiting techniques, may have some use, however it will still rely on the distribution of baits by aircraft, over an extensive area.

Dr John Read and colleagues have recently trialed and published an alternative strategy for controlling feral cats. This alternative technique relies on toxin delivery through compulsive oral grooming as a mechanism for poison delivery. As with Curiosity®, the poison being trialed is PAPP. This poison is considered best-practice world-wide and is analogous to the animal going into a sleep from which they do not wake up. The RSPCA have also indicated they believe the cats die a humane death.

In summary, the cats walk through an area with passive infrared sensors which determine the profile of the animal and the walk through trap then delivers a small dose of poison gel to the back of the cat. The cat then consumes the poison whilst grooming itself. The positioning of the passive infrared sensors is also used to minimise the risk to non-target species as the unit will only squirt gel if the correct animal profile is present.

Key advantages of the walk-past grooming traps over conventional cat control techniques include:

• No physical barrier to deter access by cats;
• Ability to use non food-based lures to dose target animals when they are not hungry;
• Improved target specificity by preventing smaller and larger non-target species from being sprayed;
• An adjustable sensor array to allow tailoring for local conditions and non-target species;
• Instantaneous administration of a measured dose of a humane poison; and
• Potential to deliver multiple lethal doses over extended periods without intervention or disturbance.

Since initially trialing this technique, Dr Read and colleagues have further refined the techniques, and have received an innovation voucher and engaged an engineering design company to optimise the delivery of the poison. Early indications are that the new walk through devices could deliver the poison across many metres in a split second, so that cats using vehicle tracks can be controlled without the need to attract them to baits or check traps etc.

This is a great initiative and one that Terrestrial Ecosystems will continue to support in the hope that we will one day find a method (or group of methods) to control feral cats across Australia. The full journal article can be found here and if you can’t download it, email John Read for a copy or to discuss this alternative idea further.