NOT TOO HOT, NOT TOO COLD: GETTING GREATER GLIDER NEST BOXES JUST RIGHT!

Update 5 July 2022: Greater gliders have officially been uplisted from 'Vulnerable' to 'Endangered'. Their populations have crashed by as much as 80% in the last 20 years due to habitat destruction including land-clearing and logging, as well as bushfires fuelled by a rapidly changing climate. Find out more...

Once upon a time, in the eucalypt forests of eastern Australia, there lived the world’s largest gliding marsupial, the greater glider.

“The greater glider is a specialist in eating eucalypt leaves,” says Dr Kara Youngentob, a Wildlife Ecologist at the Australian National University (ANU). “Unfortunately, though, it often plays second fiddle to the koala. They're much harder to see, and they live in places where people tend not to be, so they're often unknown. But when you do see them, they're just the most fascinating animal.”

The devastating bushfires of 2019-20 destroyed close to a third of all greater glider habitat. Now, this fascinating nocturnal animal, about the size of a cat, though only a fraction of the weight, is experiencing its most existential threat to date. “Greater gliders use hollows to nest in,” explains Dr Youngentob, “and they prefer hollows from really old trees; trees that can take eighty to a hundred years to form their hollows.”

With so many old trees already lost to logging, land clearing and an increase in catastrophic fires due to worsening climate change, the already under threat greater glider faces an even greater shortage of the tree hollows crucial to their survival.

To build resilience into these landscapes and help greater gliders move back into burnt areas, WWF-Australia in partnership with Greening Australia and ANU, set about creating hi-tech nest boxes, which mimic the hollows of old trees.

"I've affectionately been calling them Goldilocks Boxes,” says Dr Kita Ashman, Threatened Species and Climate Adaption Ecologist at WWF-Australia. “Greater gliders have thermal requirements. They can't get too hot and it's also good if they don't get too cold. We need a nest box that's going to be able to buffer them from those extreme temperatures, so we wanted to design something with our partners that was going to prevent that from happening. Something that's going to keep them not too hot, not too cold, but just that perfect temperature where they can become more resilient in these climate change scenarios.”

To create a nest box that best simulates the natural environment of an old tree hollow, the team has made use of many different materials.

Drew Liepa, the Senior Program Officer at Greening Australia says, “The base material for the nest boxes is marine ply. There's also a reflective paint product, which is fire retardant. Internally the nest boxes are lined with a hardwood ply between the internal insulation, with an air gap to help the box perform thermally.”

The fire-retardant paint was also chosen for its ability to reflect up to 70% of the radiant heat from the sun. Brad Blake, the Project Manager at ProCon Pest & Wildlife Management, says, “We just started really thinking about what they need in the natural habitat, and then trying to copy that basically, and trying to get longevity in these boxes too. We're still constantly redesigning the boxes and looking at all the different kinds of boxes to build for this species.”

The project so far has deployed 240 nest boxes in total, 120 in East Gippsland and another 120 in Tallaganda National Park.

Jenna Ridley, a PhD researcher at ANU, says, “These nest box sites were chosen based on greater glider abundance. We wanted to make sure that greater gliders were in the vicinity of the sites before putting them up as they're pretty slow dispersing animals which means they typically don’t move into new areas very quickly. We also wanted to ensure that these areas had been burnt, and we wanted to make sure that the habitat was older so that it actually had the potential for greater gliders to want to live there into the future.”

But it’s not just the areas they need to choose, it’s the individual trees as well. Jenna Ridley explains, “Greater gliders prefer to be very high up in the canopy of the tree, so when we pick the individual trees in which the nest boxes go, we're looking for height, we're looking for a big tree that is safe for tree climbers, and we want something that is surrounded by good habitat, so into the future, it will be habitable if they happen to take over the nest boxes and reproduce.”

It's a big project involving many people and lots of work.Still, according to Jenna Ridley, this project is not just crucial for the future of greater gliders but also the future of science and it couldn’t have happened without the dedicated team behind it. “The greater glider nest box project has been highly collaborative,” Jenna said. “It has involved so many people. We could not have done this project without WWF. They have provided excellent leadership and coordination skills. They've also provided funding and been involved every step of the way. They are really committed to ensuring that the future of the greater gliders is a good one.”

Though Drew Liepa concedes, “While it would be preferable to have natural hollows in our bush, nest boxes are the best alternative.”

The greater glider Next Generation Nest Box project is a part of WWF-Australia’s ambitious plan to Regenerate Australia in the wake of the 2019-20 bushfires through rehabilitation, repopulation and wildlife restoration to help future-proof Australia against the impacts of climate change.

What more can you do to help greater gliders?

• Find out more about the team helping to give greater gliders a fighting chance of survival
• Donate to the wildlife extinction crisis appeal
• Sign up to Regenerate Australia
• Find out more about greater gliders