Sly fox evades hunt for years, holding up reintroduction of native species in Pilliga forest, NSW

It's almost as if he knows where the cameras are: "Rambo" continues to frustrate his hunters. (Supplied: Australian Wildlife Conservancy)

For three years, wildlife conservationists have been in pursuit of an elusive fox deep in predator heaven — a wildlife haven in the Pilliga conservation reserve in north-west NSW — but they remain committed to capturing it.

The fox, nicknamed "Rambo", after the lead character from the 1982 film First Blood, is trapped in the forest, a 5,800-hectare fenced area about 90 minutes' drive south-west of Narrabri, that should be a safe place for near-extinct native animals.

"It's been a long battle," Australian Wildlife Conservancy's (AWC) Wayne Sparrow said.

"He's a particularly reclusive animal. He shies away from any human interaction.

"There were other animals in the fenced area when we locked it up and we've been able to successfully eradicate those within a reasonably quick timeframe, but Rambo continues to evade our capture effort.

Infra-red drone technology is one of many tools the team is using to try and find Rambo. (Supplied: Australian Wildlife Conservancy)

The fox, believed to be a three-year-old male, has avoided almost 3,000 baits; shooters have spent 465 hours hunting him and scent-tracking dogs were unable to find him after three weeks.

Drones and aerial shoots have also come up short.

"He's no typical fox," Mr Sparrow said.

The average lifespan of a red fox is five to six years, but "waiting Rambo out siege-style" was not the answer.

Mr Sparrow says "Rambo" turns up on film every few months. (Supplied: Australian Wildlife Conservancy)

There are 97 cameras dotted around the forest and Rambo turns up every three months or so.

When he has been photographed, it's almost as if he's posing.

"So, we've mixed our cameras up, moved them 500 metres or so away from where they were, and we've started picking him up again."

Haven repopulation behind schedule

While the intriguing cat-and-mouse game is frustrating would-be captors, it has also held up the reintroduction of regionally extinct mammals to the Pilliga Forest by about 18 months.

Small populations of bridled nailtail wallabies and greater bilbies have started breeding in the forest but some other mammals "haven't been in this area for 80 to 100 years", Mr Sparrow said.

"They're in a 680-hectare safe haven area but having Rambo in the broader fenced area is halting the reintroductions of another five species," he said.

"[They'll] go in there as soon as we get rid of Rambo."

Scent-tracking dogs are again on site for the next 10 days, pursuing Rambo in the thick bushland.

"We've had two interactions with [scent-tracking dogs] in the past, so that's our next best option," Mr Sparrow said.