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TRANSCRIPT:
Fred Ford is a Senior Threatened Species Officer with the New South Wales Department of Climate Change, Energy, Environment and Water.
He was sifting through hundreds of thousands of images when he saw something incredible.
"It just instantly struck me what it was. I was, sort of, sitting here shaking for some time."
He was looking at a photo of a Leadbeater's Possum, a species that's been presumed extinct in New South Wales for a very long time.
It was believed to be extinct in Victoria too - until it was rediscovered in 1961, and elevated to the status of that state's faunal emblem.
Victoria still lists the species as critically endangered - and Mr Ford wasn't expecting to find this particular possum hundreds of kilometres from its nearest known location.
"You can confuse these guys with sugar gliders if you're not looking for them. But if you've got the search pattern in your brain and you're sort of open to the fact that something unusual might be there, you know what it is, but there's absolutely no way I was going to start ringing people up and saying, 'hey, I've found a Leadbeater's possum' until getting it confirmed by David Lindenmayer and Dan Harley as the species experts that have been working on these things for decades, because it's just too good to be true.
Professor David Lindenmayer is with the Australian National University's Fenner School of the Environment and Society.
"Okay, so Leadbeater's possum is about 120 grams as an adult. So if you think about that, that's about four Leadbeater's possums makes it punnet of margarine in terms of body weight. So it's a small animal that will fit in the palm of your hand, and it's got a very characteristic long tail that's pinched at the base where it attaches to the body and then it looks like a little baseball bat that's sort of club shaped."
Decades ago, Leadbeater's possums were central to Professor Lindenmayer's PhD.
He spent a long time looking for them in Kosciuszko National Park, where the species has now been discovered.
DAVID: "And sadly I didn't find any animals. I did lots of spotlighting with a very powerful light. At nighttime, I mimicked the alarm calls of animals because that often brings them in."
TEE: "What does the alarm call sound like?"
DAVID: The alarm call sounds like this. I'll mimic it for you. It goes **** and it's made by adult animals in a colony. So Leadbeater's Possum lives as a colony of up to 12 individuals."
Fred Ford says it's not known how many Leadbeater's Possums are living in Kosciuszko National Park.
"So the way that we survey for most species now is actually by setting out camera arrays using wildlife cameras."
Those cameras will pick up any species that passes by, so scientists keep an eye out for all kinds of species.
One of the ways scientists know what to look for is by examining the diet of predators - in this case, owls.
"So, the prey remains of owls that have eaten something, they eat their prey whole, and then they regurgitate the bones into the caves at Yarrangobilly Caves when they're roosting during the day in the dark. And there's a whole bunch of other species in those bone deposits sitting on the surface. And we've dated them and know that they're less than 200 years old. So we know that naturally there's a number of species which have never been recorded in the area that could be recorded."
Now that the Leadbeater's Possum has been recorded, Mr Ford is now sifting back through historical archives to search for more individuals with the help of A-I.
His team is also launching a program of field work on the ground.
"So the two sites that we now have images from, they're already almost 30 kilometres apart and they're in what is a fairly common and widespread forest types through Kosciuszko and some of the adjoining national parks and state forests. So the potential search area is vast, certainly tens of thousands of hectares distributed over almost 150 kilometres or pushing up towards a hundred kilometres definitely."
A team of 10 to 15 people - including some from interstate - will set up and monitor a group of between one and three hundred cameras.
As soon as researchers have a clearer idea of where the possum populations are, they'll start implementing plans to protect them.
Although Leadbeater's Possums live in the mid-storey, they still face a significant threat from feral predators.
"And when they do come to the ground, they're exposed to things like cats and foxes, which is one of the things that's probably affecting their population size. And that's where the relationship to management really comes in."
One of those management practices is controlled burning.
"We know that we need to think about how we're burning when we're burning and what we do after a burn or after a wildfire as well in terms of following those things up with predator management, that means that if possums are forced to come to the ground because they don't have that mid story, that they're protected as much as we can from those sorts of threats."
Another way biologists are working to protect the species is through captive breeding.
There's a santuary at Healesville, run by Zoos Victoria, where Darcy Watchorn is a Threatened Species Biologist.
"Since 2012, the zoo established a conservation breeding programme looking to improve both the rate of breeding and also the genetic diversity of the species. And it's taken a little while to have some success, but just recently we have finally started to crack the code with lead be's possum breeding."
The sanctuary currently has 31 Leadbeater's Possums.
They've managed to breed one so far, but after changes to their diet of saps and insects, they're hopeful of breeding more soon.
The sanctuary has also translocated possums to try and establish more populations, in case fire or feral animals wipe out one of the few remaining Victorian strongholds.
"Both transplant patients were going really well, as I said, that there was good site fidelity and posses were lacking breeding, but then they fell over really quickly once feral cats most likely clued into them."
Another reason the sanctuary is so important is because the small population of possums that survive in Victoria are also threatened by declining genetic diversity.
Researchers suspect one of the two sub-species Victoria hosts is down to 30 or 40 individuals.
The sanctuary is working on boosting genetic diversity by inter-breeding the two populations, and they've also set up a new fenced reserve to establish a protected population in the wild.
They're waiting anxiously to learn more about the genetics of population discovered in NSW, work Professor David Lindenmayer will be part of.
"So hopefully in the next year or so, my little group of scientists and New South Wales Park Service will be able to work together to make sure that we can secure this population, which is not likely to be very large. And it's quite likely to be a separate subspecies from the ones in Central Victoria, because it's such a long way away."
The unlikely discovery has caused huge excitement among scientists and conservationists.
But it has prompted renewed called for greater protection for one of the world's most endangered creatures.
"I think to quite important to really highlight that their discovery in New South Wales really shouldn't have any impact on the conservation actions that are underway for the Victorian populations because those threats are so perverse and the population is so imperilled."
