Tony Cathcart, a quiet sort of bloke nearing 50, once spent 187 nights hunting a tabby cat through the red earth desert between Mildura on the River Murray and Broken Hill in far western NSW.
''In that time I saw it once and I saw its prints twice,'' he recalls. But that was enough. He knew it was there and he kept up his lonely hunt. ''Every night I would drive down the same track and put my traps out.''
On that 187th night, the cat pawed some rabbit meat from one of Cathcart's traps and was caught in its firm rubber jaws.
The following morning Cathcart found his tormentor, a little female, just 3.5 kilos. Small for a feral.
In the soft dawn light Cathcart shot her in the head, killing the last introduced predator inside the fences of a 6000-hectare animal sanctuary. It had taken him 18 months to kill them all.
''I had a few quiet moments,'' he says. ''She was a worthy adversary, but she had to go.''
The sanctuary is a haven within a haven for six threatened mammals that have been reintroduced inside its 54 kilometres of feral-proof fencing. They are the woylie, the bilby, the numbat, the bridled nailtail wallaby, the burrowing betong and the stick-net rat.
The fenced zone sits inside Scotia, a 65,000-hectare property owned by the private not-for-profit organisation Australian Wildlife Conservancy. In that larger area, known as the buffer zone, feral numbers are kept down by Cathcart's constant baiting, trapping and shooting.
Climbing out of a four-wheel-drive to meet us by the side of the road two hours' drive south of Broken Hill, the AWC ecologist in charge of programs in south-eastern Australia, Dr Matt Hayward, looks a local but he was schooled in Sydney and arrived in the Mallee via a stint in South African big-game parks.
After an hour on the rough desert road we come to the fence. Hayward opens a sliding gate that would not look out of place in a prison. The chain-link fence topped by three strands of electric wire is as high as a tall man and cantilevered at the top to stop any animal cunning or determined enough to climb it.
Hayward explains that the fencing - which costs $17,000 a kilometre - is checked every two days. Damage is normally caused by buck kangaroos fighting through it, one on each side. ''The ones on the outside keep getting shocked every time they kick,'' says Hayward. ''They don't know what is hitting them but they keep fighting.''
He tells us the remarkable story of the animal we've come to see, the nailtail wallaby.
These little creatures were listed as extinct for most of last century until a Queensland shearer was sitting on a dunny reading a New Idea story about Australia's lost mammals and recognised a nailtail in a photo.
''I know where there's a mob of them,'' he thought to himself, and soon convinced authorities to follow him to a remote Queensland redoubt where a tiny remnant population was holding on.
Soon we are joined at the fence line by Cathcart, the Scotia manager and pest control officer. He demolishes Hayward's story. It was a fencer, not a shearer, a hospital waiting room not a dunny and a Woman's Day.
Either way, some the animals were relocated to Scotia and we are being driven into the breeding enclosure to meet them. We expect it could take some time. Perhaps we'll have to wait out the afternoon and use spotlights. Perhaps they'll be a distant blur.
Suddenly, a bored-looking wallaby is sitting before us between the ruts in the dirt road. There are more ahead.
The little wallabies have black markings around the shoulders and chest. Towards the end of the tails is a spike, or nail, though it can't be seen from a distance. They have wet brown eyes, fine features, and fully grown they are the size of a toddler.
Just 12 of the animals were bought to Scotia in the late 1990s when it was owed by John Walmsley, the man famous for his cat-skin hat. His company, Earth Sanctuaries, was listed on the stock exchange but collapsed. Scotia was taken over by Australian Wildlife Conservancy. Today there are 2500 nailtails inside the fence.
This is where some controversy lies. Some argue that the AWC, a private organisation with 22 sanctuaries across Australia on 2.6 million hectares, is creating de facto zoos rather than re-creating safe wild zones.
Hayward disagrees. Outside the breeding area but within the fence line, he says, Scotia's animals live wild, but free of introduced pests.
The difference in the landscape of the fenced area is hard to detect after all the rain, he says. But in the dry season it looks like an oasis compared to the land outside. Not only are the animals protected from predators, but the grasses and bushes flourish without rabbits. Even juvenile trees are beginning to regrow. It is, says Hayward, how Australia might have looked before Europeans arrived.
Once the nailtails' range covered most of eastern Australia but they fell victim to cats, dogs and foxes.
We drive on at walking pace, careful not to run over any endangered species. Two nailtails rut complacently in the middle of the road, the buck keeping an eye us, the doe looking off into the bush. We laugh as Herald photographer Kate Geraghty intrudes on the moment, and Cathcart observes that such an act has probably never been photographed before.
In July AWC released 60 nailtails into the unfenced buffer zone, 40 of them with radio collars. Of the collared animals 26 survive. The death rate dropped as the survivors learnt to cope with predators. At this rate the population might grow.
Cathcart's path to Scotia was longer than Hayward's. He was born and raised in the west and has done everything from shearing to working as a laboratory technician. He has been both a shooter and a bird watcher all that time.
He first became serious about the need to cull pests while walking in the Warrumbungles when he saw a cat kill a sleeping cockatoo.
He uses traps that are ingeniously designed to take target animals, poisons that have little effect on natives, and finally, when the feral numbers are low, he resorts to the rifle.
We drive on to a grove of she-oaks spared by the pastoralists who once chained this land. The sunset breeze is beginning to sing through the needle leaves.
Hayward proudly shows a patch of churned and potholed dirt the size of two basketball courts.
''Tony saw a pair of bilbies do this in a just a couple of days,'' he says. The animals burrow into the ground for food and Hayward points out how the holes are beginning to fill with decomposing leaf litter. The topsoil is already benefiting from the bilbies' work.
Cathcart says that in the old days horsemen had to lead their animals on foot for days in this region because of the bilbies and their dangerous little holes.
Photographer Geraghty yelps and jumps as something skitters past her feet. ''A numbat!'' cries Hayward as if he has just seen a full-time try. Cathcart, who had been 50 paces away showing me little nuggets of echidna scat in the palm of his hand, mutters to me. ''A numbat. Do you know how often I see a numbat? Twice in a good year. That is cruel.''
Next we go to see the nailtails living outside the breeding enclosure, but inside the fence line.
They roam the fringes of the runway, wary rather than fearful. Also scratching for food among the saltbush are burrowing betongs, a species once extinct on the mainland which Hayward says ''is going gangbusters'' inside the fences. . AWC released some once in Western Australia: a dingo took 17 the first night.
The animals don't fear us, but they are wary and keep their distance. Their numbers are growing fast though they are still prey to native eagles and owls.
Hayward does not believe the AWC sanctuaries will save Australia's endangered species.
He does believe enough of them, spread over the continent, might serve as a network of parks, though, and keep the animals alive until we find a way to be rid of the introduced predators, or at least give the remnant populations time to learn how to cope with them.
On the drive back to Broken Hill the stars are bright but it is dark without a moon. About an hour from town a great white shape launches itself towards us from the side of the road. A barn owl feeding on road kill. It fills the windscreen in a flash and there is a thud on the driver's side.
We try to tell ourselves it was a glancing blow, but then we notice the side mirror has been pressed flat against the body of the car. It is hard to believe it had much of a chance.