Robotic traps equipped with artificial intelligence are being used in a trial to control feral cats in Queensland's World Heritage-listed wet tropics area, near Cairns.
Queensland Parks and Wildlife Rangers are trialling grooming traps which use light and image sensing technology to detect movement and artificial intelligence to determine if what it detects is indeed a cat.
The trial in Wooroonooran National Park is the first time the "Felixer" traps have been used in a tropical Australian rainforest.
The technology has already been trialled in all other Australian states and territories.
Innisfail-based ranger Chris Roach says when the Felixer's artificial intelligence confirms its target as a feral cat, it shoots a tiny gel pellet containing sodium fluoroacetate, known as 1080 poison, onto the animal's fur.
"Because cats are such fastidious groomers they lick that gel straight off and that's the end of that cat," Mr Roach said.
"It's only 3 millilitres of gel and it contains only 8 milligrams of 1080 in it — so it's a very small amount, because cats are very susceptible to 1080.
"What we've got is a unit that is species-specific and one that will only target cats."
Mr Roach said the trap was tested in a non-lethal, camera-only mode for six months before it was loaded with pellets, and no animals other than feral cats had been killed by it during the trial.
The trap's developers, Thylation, state on their website there is some risk dingo pups could be targeted but Mr Roach said dingoes and other animals had passed the traps without activating them during the trial.
'Shocking' cat numbers in wet tropics
Feral cats are among the biggest killers of native wildlife in Australia, and in far north Queensland also compete with native spotted-tailed quolls for food and habitat.
University of Queensland researcher Tom Bruce recently led the first ever systematic study of feral cat populations in the wet tropics and found the animals were distributed throughout the region, in far greater numbers than previously thought.
"I went to seven different sites which covered about 200 kilometres in the wet tropics and put camera traps every two kilometres along major roads and trails in the area," Mr Bruce said.
"It was frankly shocking to see that they were in every national park and state forest that I went in when people had predicted they weren't going to be there."
Mr Bruce said his study and previous research into feral cat behaviour suggests they use roads through national parks.
"The road almost acts like a highway for cats ... to make it easier to cross the forest and move to different patches within national parks."
Mr Roach said the trap trial was showing promising results.
"Feral cat control is notoriously difficult, no matter where you are, and when you put it into a remote rainforest situation it suddenly gets a lot more difficult," Mr Roach said.
"We're two months into a three-month trial and we're only targeting a 10-kilometre stretch of road, so quite a small area, but have removed 25 cats from that area."
Development of the Felixer trap was partly funded by the Australian government, land management groups and other non-government organisations.