Bush invention helping trap feral cats

Murray Schofield was bouncing along a rocky track near Cape Hart on Kangaroo Island's Dudley Peninsula, checking feral cat traps.

It was a 20-minute drive in, a 20-minute drive out, and too often the trap held no cat. Instead, Schofield was releasing native bush rats and possums.

"Basically, after doing that 40-odd times, I got the shits," he says.

So he built something different.

The result was the Double Lure trap, known to the Kangaroo Island feral cat team as the DL. It is a deceptively simple piece of kit: two cage traps joined to form a longer tunnel, with cat urine used as the lure instead of food.

The idea is to make use of a cat's territorial instincts and curiosity. A cat smells urine, moves into the tunnel to investigate whether another cat is in the area, walks further than it would in a standard trap, passes the foot plate, and is caught.

"The DL doubles the length the cat has to move over before it hits the foot plate," Schofield says.

"Cats love going into tunnels. The DL is like a big tunnel."

It also helps reduce off-target captures.

"There's no food for the native bush rats and possums," Schofield says. "The cats are interested in the smell of the urine."

For Schofield, 54, who lives at Western River, the trap is not something to make a fuss about. He is not the type. Relaxed, dry and self-effacing, he speaks about it as if it was simply the obvious thing to do after too many long drives and too many empty results.

But the results have given the feral cat team reason to pay attention.

From 1 January to 22 June 2026, program figures show that 60 DL traps captured 52 feral cats on the Dudley Peninsula. Over the same period, 600 cage traps captured 32 cats and 40 leg-hold traps captured 30.

The figures are not a controlled comparison: each method is deployed differently and in different circumstances. The DL is not replacing other tools. But for a specialist team trying to catch an increasingly scarce and difficult target, it has become a valuable addition.

That is where the work becomes harder.

At the start of an eradication program, feral cats are more common and easier to encounter. Later, the remaining animals are fewer, more scattered and often more difficult to catch. The job shifts from broadscale control to precision eradication.

"There are fewer cats and less scent around the place," Schofield says. "So, there is more chance of the remaining cats going into the DL."

A three-kilometre predator-proof barrier spans the narrowest point of the Pelican Lagoon isthmus, physically separating the 38,400-hectare Dudley Peninsula from the rest of the island and preventing cats from moving back into the eradication zone.

The program aims to reduce the remaining feral cat population by more than 95 per cent during the 2026 winter knockdown before moving into mop-up operations and a 24-month monitoring phase to confirm proof of absence.

The work has national significance. Kangaroo Island is one of 20 priority places under the Australian Government's Threatened Species Action Plan. Across Australia, feral cats kill more than 1.5 billion native mammals, birds, reptiles and frogs each year and have helped drive more than 20 Australian mammal extinctions.

On Kangaroo Island, where there are no foxes, feral cats are the apex predator. They prey on vulnerable native species including the Kangaroo Island dunnart and southern brown bandicoot, as well as little penguins and other wildlife. They also threaten primary production by spreading diseases that can affect sheep.

For the eradication team, the final stage is less about removing large numbers of cats than solving a series of individual problems. One animal may avoid a cage trap. Another may move only at night or stay close to houses. Some become trap shy. Each remaining cat can require a different combination of surveillance, patience and tools.

Schofield's own path to Kangaroo Island reads like a map of practical Australian bush work.

He grew up near Cooma in New South Wales, on a sheep and cattle farm managed by his father. He worked as a shearer, a station hand and a ringer on cattle stations in far north Australia before returning to Cooma to work as a dog trapper for Local Land Services, stopping wild dogs coming out of national parks and killing sheep.

After the 2019-20 Black Summer fires, the Australian Wildlife Conservancy brought him to Kangaroo Island to work at Western River Refuge, focusing on Kangaroo Island dunnart protection and feral cat control around Western River and Snug Cove.

After a period back in New South Wales repairing bushfire-damaged fencing, he returned to Kangaroo Island in 2022 and resumed feral cat work on private properties.

The idea for the DL came in 2023, when Schofield was working two days a week for Australian Wildlife Conservancy. At the time, restrictions on where leg-hold traps could be used meant the team needed other options around homes and conservation areas.

The restriction forced them to think harder about what else could work. That practical problem-solving has become central to the program as cat numbers decline and the remaining animals become more difficult to predict.

Schofield says the DL is particularly useful because it can be used by landholders as well as professional trappers.

"It takes time to learn how to set traps effectively," he says. "It takes even longer before you can specialise in using leg-hold traps. You need to take your time and get it right because cats are clever and do become trap shy."

After the first DL caught a cat, Schofield built more and kept catching cats. Soon after, his colleague at the Kangaroo Island Landscape Board, Cheryl Ann Monks, built another 30 in a couple of days. They have since been deployed across the landscape.

Schofield is blunt about the limits of any single method.

"It is important to note that some cats will never go into the DL or any trap," he says.

"We need to use every tool in our toolkit for total eradication."

That toolkit is extensive, and no single method is expected to find every cat.

AI-assisted cameras help identify where remaining animals are moving. Thermal drones and vehicle-mounted thermal optics help field staff detect cats at night. Trap alerts allow equipment to be monitored more efficiently. Skilled practitioners use cage traps, soft-jaw leg-hold traps and specialist trapping techniques, while detection dogs can locate cats and signs of activity as numbers decline.

The technology matters, but so does what happens between detections. Every trap location, camera image, track, scat, sighting and failed attempt adds to the team's understanding of what individual cats are doing.

That is what makes eradication different from control. The measure of success is not just reducing numbers. It is finding the last feral animals.

Schofield does not describe it that way. He is more comfortable talking about what works, what does not, and what he will try next.

He has the understated manner of someone who has spent a lot of time working alone in large landscapes. Private, practical and quietly funny, he is more likely to underplay an achievement than promote it.

The DL says plenty on his behalf.

It is not a glossy invention from a city laboratory. It is a bush solution developed by someone who understood the target animal, the landscape, the limits of existing tools and the importance of not wasting time.

And somewhere on Kangaroo Island, a long cage baited not with food but with the scent of another cat is waiting in the scrub - a simple trap designed by a man who got sick of releasing possums and helped give one of Australia's most ambitious feral cat eradication programs another edge.

Acknowledgements:

The Dudley Peninsula Feral Cat Eradication Program is delivered by the Kangaroo Island Landscape Board, with support from the Penneshaw Progress Association, Kangaroo Island Council, Agriculture Kangaroo Island, Kangaroo Island Tourism Alliance, Kangaroo Island Business and Brand Alliance, Antechamber Bay Action Group, Invasive Species Council, Dudley Peninsula primary producers, business owners and community members, and technology partners including Encounter Solutions, ethos Environmental and eVorta.

The program is funded by the Australian Government, the Government of South Australia, the Ian Potter Foundation and the Purryburry Trust.