"We have just discovered high altitude koalas in the World Heritage Blue Mountains region, living at over 1000m. Not only that, but they were found on the top of a ridge in what most experts would class as poor quality and highly unlikely habitat," writes Dr Kellie Leigh, the executive director of Science for Wildlife and BMWHI board member.

"All species have limits to the type of habitats they can use, some habitats are too unsuitable for them to occupy. The general rule for koalas is that they occur below 800m in altitude, and prefer forests on richer soil types.

"But wait, this gets better.

"Sometimes we find male koalas in poorer habitats; they can be forced to use them when they’re pushed out by other males, or they might move high up on a ridge so that their mating bellows carry further. So if it’s a male koala that we find we don’t necessarily assume he is in core koala habitat. The breeding females tend to occupy the best quality habitats to meet their nutritional needs while raising young.

"What we found on this ridgeline at over 1000m was a cluster of breeding females all carrying young joeys like Pluto. That makes it core koala habitat. None of us could believe what we were seeing, this is a game changer."