Eight new, tiny, spotted residents of Mulligans Flat carried strange electronic objects around their necks and newborn babies in their pouches.
The quolls sniffed around the undergrowth, looking for signs in the odd environment - signs that this might be a place they could survive, even thrive.
They also carried the weight of hope and expectation for researchers at the Australian National University; researchers who had been hurt before.
Dr Belinda Wilson, a postdoctoral research fellow at the Fenner School of Environment and Society, said academics have learned a lot from the previous quoll trials at Mulligans Flat.
"The fence design has a floppy top and it's only one-sided," she said.
"Things can't get in but they can certainly get out. The quolls surprised us; they were very keen to climb out into the surrounding landscape."
In 2016, eastern quolls were reintroduced into the ACT for the first time since their effective mainland extinction in 1963.
Initial hopes for the marsupial were dashed when a fence designed to keep out foxes and other ground-based predators proved ineffective at containing the quolls.
Many escaped, and the overall survival rate of the first trial was only 28.6 per cent.
The trick, Dr Wilson said, was not trying to keep them contained, but instead providing them with a place where they wanted to stay.
"We can't control their dispersal, they can do what they want," she said. "The question is how do we make Mulligans Flat as attractive as possible?"
"Being born in the sanctuary makes them more familiar with the landscape."
The latest trial was designed to test whether new quolls introduced into the area would be shunned or accepted.
A single den of seven quolls, both resident and introduced, soon answered that question.
Changing the gender of the animals introduced also proved to be a masterstroke, with new female quolls surviving at much higher rates than their male counterparts.
"You want to put in both males and females. [But] the males were just running around looking for habitat and didn't really find anything that would indicate 'this is a good quoll spot'. They overdispersed," Dr Wilson said.
"In the second and third introductions, we introduced only females with pouch young, which means they anchored to the site. We were able to markedly improve the survival rates."
As a result, the Mulligans Flat sanctuary is now producing more quolls than they can possibly hold.
A notoriously boom-or-bust animal, the number of quolls in the sanctuary can vary hugely, but Dr Wilson said that now, at the back end of the mating season, there are 50-60 breeding adults - so many that the Mulligans Flat researchers are trading quolls with other sanctuaries in Mount Rothwell and Tiverton.
"It's a very live-fast, die-fast species. It'll ramp up to over 100 and drop to 50 over the course of the year," Dr Wilson said.
She encouraged anyone who wants to see the quolls to book a twilight tour at the new Wildbark sanctuary.
