When Daryn McKenny spotted a koala in the state conservation area he has considered his "backyard" for decades, he knew it was an important find.
It was the summer of 2019-2020 when catastrophic bushfires hit Australia's east coast and Mr McKenny spied a koala on a trail camera he'd set up at Sugarloaf State Conservation Area, inland of Newcastle.
"I grew up near Sugarloaf. This was my backyard as a kid ... I'd never seen a koala there before," the Gamilaraay and Wiradjuri man told AAP.
When Mr McKenny called the University of Newcastle about his find, they told him they weren't aware of a koala population at Sugarloaf.
Armed with a head torch and his knowledge of the Country he grew up exploring, Mr McKenny spent the next few years gathering hundreds of videos and photos of the marsupial.
Dr Ryan Witt and Daryn McKenny doing a thermal drone survey for koalas at Sugarloaf State Conservation Area.
"Western ecologists will tell you you look for white eyes.
"I don't look for white eyes.
"I look for tree stars – their eyes are bright – we'd see blinking stars in the trees, that's when I knew I was seeing a koala."
University of Newcastle researchers worked alongside Mr McKenny to survey the koala population at Sugarloaf as part of a statewide study on the species.
Using spotlighting methods and thermal drone searches, they found a significant population of more than 290 koalas.
"We didn't determine that we have a colony of koalas living on the fringe of a city - we actually have a city of koalas living on the fringe of an urban population," Mr McKenny said.
University of Newcastle conservation scientist and study co-author Ryan Witt said Mr McKenny had a huge amount of knowledge of the land and koalas at Sugarloaf, which was helpful during the survey.
"We were grateful to learn from him and share methods to find these cryptic animals," Dr Witt said.
Koalas are listed as endangered in Queensland, NSW and the ACT.
The statewide survey estimated a total population of more than 4000 koalas across 67,300 hectares of bushland.
Of the seven national parks surveyed, Maria National Park had the greatest density of koalas with 521 predicted in 3350 hectares.
Areas affected by the 2019-2020 bushfires had fewer koalas in comparison to the national parks that weren't impacted.
"What's important to understand is it's not just where koalas are, but where they're not, and understanding why koalas aren't in certain areas, particularly if there's high-quality habitat there," lead researcher Shelby Ryan said.
"That can help inform us about current koala populations and their threats and their likelihood of decline or localised extinction."
