The Hunter River Times

Within the Yengo National Park, the Wollombi Glider Live Tree Hollows Project stands as a central force for Australia’s enchanting gliders, attracting global attention, and achieving remarkable results. These adorable nocturnal Gliders, with large luminous eyes that glide through the air like whimsical forest spirits, are in dire need of our help, rallying communities from near and far.

The Greater Glider, with large ears and long fluffy tail, weighs approximately 1.5kgs, and the Yellow-Bellied Glider, with silky black fur and pale-yellow underbelly, known for its loud screeching calls, lighter at approximately 700 grams, has seen its populations dwindle due to habitat loss and fragmentation. The Wollombi Glider Live Tree Hollows Project is stepping up to address this, using innovative methods to provide these gliders with the homes they desperately need.

A natural hollow formation can take up to 80 years, making the project’s artificial hollow creation efforts vital for the immediate protection of these species. In Australia alone, hollows provide homes for at least 300 types of animals, including 17% of bird species, 42% of mammals, and 28% of reptiles. Worldwide, over 1000 species rely on hollows for nesting and roosting and the loss of tree hollows is a widespread concern globally, and this project has gained attention from as far as Austria.

The Hunter River Times was grateful to spend time with Euan Wilcox, the project’s lead, and over a coffee and a trip into the National Park, he graciously shared his story. Initially aimed at aiding black cockatoos, Euan began his conservation journey with a simple wish to help the wildlife on his property. “I saw this tool, the Hollowhog, and thought about making hollows for a variety of wildlife,” Euan recalls. But after consulting with ecology specialists and discussing the Hollowhog he was advised to target a specific species. “My friend, whose daughter happens to be an honours graduate in Ecology specialising in Gliders, Maaike Hoffman, was a perfect match for this project,” Euan explained. Maaike was eager to be involved and to gain hands-on experience using the Hollowhog tool.

The Greater Glider, being the largest and one of the most challenging due to its intense need for hollows, doesn’t need just one; it requires many, moving up to 20 different hollows. It desires at least a 30 to 50-meter elevation and prefers to be in the top third of the tree canopy. “This species is the most endangered, think of them like the koalas of gliders, super cute, a good size and very shy,” said Euan. He mentioned, “Studies have been conducted, and nest boxes were tried, but they don’t favour them. The humidity and temperature variations in nest boxes are too extreme, and they lack insulation. The rationale for Hollowhog is that boring into live trees provides natural insulation, temperature, and humidity control, and is a perfect situation.” Euan recalls Maaike’s advice: “If we design for the demands of the Greater Glider, then by natural effect, it cascades to all the other glider species that need it.”

Maaike shared her comments: “It is incredible to assist on such an innovative project. There is a lot of interest in the design of suitable nest boxes and hollow designs for cryptic and rare species such as Greater Gliders and Yellow-Bellied gliders so to have success in this project is truly amazing. I was excited to have such high levels of activity at each hollow and am sure that the hollows will provide much-needed homes for wildlife well into the future. I hope that as research continues, we see a shift in moving away from conventional nest box designs in favour of carving natural hollows.”

Three sites were selected based on BioNet Atlas data and fauna studies conducted after the 2019/2020 bushfires. This includes two in Wallabadah and Upper Yango Creek Road and continues to expand into 2024 given the success of the project.

Thanks to the collaboration of volunteers, arborists, consultants, Wollombi Valley Landcare, and the Hollowhog tool, with funding from the Wettenhall Environment Trust, the project has shown promising results. Euan emphasised the gliders’ rapid acceptance of the newly created hollows as a sign of success. “Seeing the Greater Glider use the hollows was exceptional,” he remarked. The numerous photographs capture gliders quickly adapting and moving into these environments—indicating they are sleeping, moving in and out, and feeling safe.

Euan highlighted Matt Stevens’ involvement from Hollowhog, noting his background as an ecologist and his excitement for the project’s specialised focus. “Matt was thrilled about our project because it targeted very specific species. We supplied him with detailed information, which allowed him to create hollows specifically designed for the needs of these species,” Euan shared. He further explained the benefits of the Hollowhog method, “One significant advantage is that it doesn’t impact the tree’s structure. The hollow will naturally grow along with the tree, making it a permanent habitat solution.”

Euan explained, “Ultimately, we developed three distinct designs. One approach involved utilising old dead logs found on the ground. We bored these out to create starter hollows, then attached them to trunks after the arborist carved out hollows directly in the trees (as pictured). This method is beneficial because, over time, the tree grows around the inserted dead log, and the two merge organically into one. We were able to produce 20 to 30 of these in advance of the arborists’ arrival. It would be fascinating to see how these evolve in 50 years.”

The project’s current results are impressive, with over 100,000 images captured by 20 cameras showcasing significant success in creating habitats for endangered glider species. Both target species have been observed utilising their new homes, with the Greater Glider notably documented. Sightings include 7,740 instances of Greater Gliders, 16,838 Squirrel Gliders, 10,186 Sugar Gliders, and 5,401 Brushtail Possums. Target species were spotted at 9 out of 21 hollows, achieving a remarkable 43% success rate.

Sparked by the song of the black cockatoo and blending design with environmental care, this project feels akin to a love letter, one that Euan and Maaike, conservationists, arborists and volunteers have crafted together, and it seems the Gliders are composing their heartfelt response.