Rambo part II: wildlife in the forest where the feral fox once roamed is thriving – but is a comeback tour likely?

<span>A bridled nailtail wallaby in the Pilliga forest, where native species are thriving following the removal of feral invaders – including, seemingly, Rambo the fox.</span><span>Photograph: Wayne Lawler/AWC</span>
A bridled nailtail wallaby in the Pilliga forest, where native species are thriving following the removal of feral invaders – including, seemingly, Rambo the fox.Photograph: Wayne Lawler/AWC

There is a baby boom of critically endangered native species happening in north-west New South Wales. For the first time in more than a century, the Pilliga scrub – the largest native forest west of the Great Dividing Range – is crawling with multiple generations of greater bilbies, bridled nailtail wallabies, brush-tailed bettong, plains mice and Shark Bay bandicoots.

“All the animals are thriving and most of the females are breeding,” says the Australian Wildlife Conservancy ecologist Vicki Stokes, who monitors the colony’s progress via camera traps and transmitters attached to their tails. “And because the bandicoots have a gestation of just 18 days and the plains mice around 30, it’s happening fast. Some of them are on their third or fourth litters already.”

The population explosion is all the more remarkable for the adversities it has overcome. Chief among them was Rambo the fox. When the 5,800-hectare conservation area was cleared and fenced in 2016, feral cats and foxes within it were killed or captured inside a month. All but Rambo, who eluded a legion of hunters, trappers, scientists and rangers for five years.

“We threw the kitchen sink at eradicating Rambo and it cost us hundreds of thousands of dollars,” says Dave Kelly, who manages the threatened species program for the NSW National Parks and Wildlife Service. “Every technique we deployed – aerial surveillance, traps, poison baits, thermal imaging – all failed. The fox was always one step ahead and the harder we tried, the smarter he seemed to get.”

Ultimately, Rambo simply disappeared. The last camera-trap footage of the fox with the distinctively torn-up ears (injuries sustained when Rambo vanquished the last feral cat in the enclosure) was in October 2022. Around that time heavy rains hit the Pilliga. When a requisite three-month monitoring period revealed no further traces, Rambo was declared “no more”.

“Even then, I wasn’t 100% convinced,” Stokes says. “If any fox could’ve worked out a way to survive, it was Rambo. In the end, those floods came at a great time. The temporary breeding area of 680 hectares was getting seriously crowded. And with the last remaining threat wiped out, the fences came down and we gave the animals free rein of the full 5,800 hectares.”

Despite not having laid tracks in the Pilliga’s red dirt for so long, the bilbies “moved fast”, says Stokes. “For a species that is over 15m years old, a century isn’t much. We found their burrows and diggings on the far side of the enclosure within a few months and they’ve now got colonies everywhere.” The wallabies, bettong and bandicoots have thrived similarly.

But the plains mice have been a challenge, Stokes admits. “They’ve been so rare for so long, a lot of what we’re discovering is new. When we released them in September we thought they’d disperse and burrow straight away. But they freaked out and sheltered under grassy clumps in the open. These adorable little lumps were snoozing when rats and antechinus attacked.”

Numbers are now recovering, as is the wider ecology. “These animals are soil engineers,” Kelly says. “They churn leaf litter and nutrients so the ground holds moisture better.” Watching how bilbies moved burrows to forage richer areas also informed Kelly’s decision to incorporate traditional fire practices. “We burn small areas regularly in a patchwork cycle as the Kamilaroi did. The animals responded fast, following the burst seeds and grass shoots.”

The Pilliga is a unique environment, dense with cypress pine (it was heavily logged until 2000) and teeming with emu, koala, long-eared bats and owls. “Even without Rambo around, the Pilliga is full of dangers,” Stokes notes. “Our five species might be rare but that doesn’t mean they’re protected from natural predators like pythons, goannas and raptors.”

So much so that Stokes says the carnivorous western quoll will lead a new wave of regionally extinct animals – numbat, red-tailed phascogale, burrowing bettong, Mitchell’s hopping mouse and greater stick-nest rat - to be rewilded in coming months. “There’ll be predation but unlike foxes, quolls are native predators with aeons of co-existence with our mammals.”

Related: ‘It’s over’: five-year hunt for Rambo the feral fox paves way for greater bilby to roam free

Of Rambo’s many enigmas (Kelly believes the fox was actually female), one was that his diet consisted almost entirely of insects. “Rambo never touched any of the meats we’d try to lure him with,” Stokes says. “And when the hunt hit its fifth year, we were having serious discussions about the bilbies and Rambo co-existing. Thankfully, he vanished before it got to that.”

“Vanished”. “Disappeared”. “No more”. Why doesn’t anyone declare Rambo “dead”? Kelly gives a wry chuckle. “We never found a body, did we? And there’s something else that nags at me. During those floods we took down a small section of fence to let the creek through. It was only for a few hours but the chance to escape was there … If anyone could, it was that fox.”