Island hideaway: has the endangered mahogany glider found a new home off the Great Barrier Reef?

If there has been rain and it’s after dark, Daryl Dickson listens for a shower of drops bumped loose from the leaves above.

When it’s dry, it could be the faint sound of the caps of bloodwood blossoms landing on her roof that sends her off to grab a torch and catch a glimpse of one of her elusive marsupial neighbours.

“I don’t think there’s anything more magnificent than seeing a big mahogany glider go over the top of you. I just think they’re beautiful,” she says.

When artist Dickson moved to Meunga Creek near Cardwell in far north Queensland almost 30 years ago, she had no clue she was sharing her home with a unique mammal.

Her block, it turns out, is not the “rubbish scrub” the real estate agent told her about.

Rather, it is prime and precious habitat for the mahogany glider, which is living a precarious existence on Earth in a thin but fragmented strip of coastal woodland just 120km long.

Australia has seven possum-like gliding marsupials, but the mahogany is the most threatened.

The earliest known specimen was collected in 1886 near Cardwell by a collector at Queensland Museum, but had lain in a drawer without ever being identified as a unique species.

In 1986 when the museum was moving, staff wondered if this much larger specimen might be a different species. After returning to the location again, staff eventually found the glider four years later. The name mahogany comes from its colour and the swamp mahogany tree – one of the important species in its habitat.

The gliders, which grow up to 28cm long and have tails up to 41cm in length, live in tree hollows and like open wet woodlands and tea tree swamps, but about 80% of their habitat has been lost.

What’s left is badly fragmented by agriculture and human settlement. Now, the glider habitat is fractured into almost 1,000 individual pieces.

The last estimate suggested there were no more than 2,000 individuals left. But that count was before 2011’s Cyclone Yasi – one of the state’s most powerful recorded cyclones that smashed the glider’s tiny bolthole.

“Since cyclone Yasi, we’re not really sure how many there are,” says Andrew Dennis, who is coordinating a five-year project to save the glider at Terrain NRM, an environmental management organisation.

“They’re actually quite hard to trap. They feed mostly on nectar and tree sap and it’s quite hard to get them attracted to a bait.”

So far, the bait that works the best for the mahogany gliders has turned out to be raspberry cordial. “We have to spray quite a bit of it around the camera and the cages,” says Dennis.

An island hideaway?

The Guardian can reveal there is hope a community of the gliders could have been hiding out for a few thousand years, unnoticed by any humans, on Hinchinbrook Island – a wilderness national park less than 10km off the coast.

Modelling of the glider’s habitat suggests the island is “high quality mahogany glider habitat”, says Dennis.

A team put up 20 camera traps on the island for six weeks and brought them in just before Christmas.

There were no mahogany gliders spotted, but in the final hours before the cameras were removed one caught an image of a sugar glider – a smaller close cousin of the mahogany.

“Finding that sugar glider is tantalising,” says Dennis. “They’re often in the same forests together with mahogany gliders.”

Researcher Eryn Chang is two years into a PhD at James Cook University. She led the work to model the gliders’ habitat and is working to understand their genetic health.

So far, she has taken tiny tissue samples from the ears of 22 gliders to analyse.

“They’re very difficult to catch,” she says. “But they’re extremely cute for sure. Anyone who handles them loves them.”

Using a flap of membrane attached to their wrists and ankles, mahogany gliders can propel themselves up to 60 metres from one tree to another. All agree it’s a wondrous sight.

“It’s magnificent to see them glide. It’s like… Wow,” says Chang.

Her genetics work will give clues about the viability of the different groups of gliders spread in small pockets around the area.

“We can then know if a population is suffering from in-breeding or if they’ve been recently connected to other groups,” she says.

If any mahogany gliders are hiding out on Hinchinbrook, then Chang wonders how being cut off from other populations will have affected their genetic diversity.

How much might the gliders have changed over thousands of years of isolation? Could they really have survived there? She hopes they’re questions she’ll get to investigate.

Even if mahogany gliders are not found on the island, Dennis says Hinchinbrook could be an option in the future as a refuge to relocate some mahogany gliders to live without many of the threats they face on the mainland.

Help for the vulnerable

A large group of stakeholders from local, state and federal government agencies, conservation groups, Indigenous Girringun rangers and plantation managers have completed a draft national recovery plan for the mahogany glider. The plan is currently with federal environment minister Sussan Ley for final approval.

Terrain NRM is working with Indigenous rangers to carry out controlled cool burns.

Historically, Indigenous groups managed the glider habitat with fire that kept rainforest vegetation out and retained the woodland trees that gliders prefer.

As clearing and development along the coast has made the gaps between trees wider, the gliders have struggled to make the distance, often getting caught on barbed wire.

There’s also work with landholders and volunteers to plant trees to create corridors and to replace the barbed wires at the top of fences with plain wire.

The gliders are awkward and vulnerable on the ground. Poles resembling wire-free telegraph poles have gone up in 10 locations to help them bridge gaps over roads and fields. Cameras have caught the gliders using them.

“There’s this sound of a glider landing on a tree trunk – like a whack and then a scratch. You’ll then hear a little scamper up the trunk,” says Dennis.

Dickson and husband Geoff have nursed about 25 wounded mahogany gliders over the years, mostly with injuries caused by their flying membrane being snagged on fences.

Most years one or two mahoganies arrive for care with Dickson. But after Yasi hit, there was a seven-year gap until the next one arrived. Three gliders have been dropped at her small sanctuary for care in the past three years.

The first gliders arrived at Dickson’s home in 2000 in the form of two tiny 19 gram “jellybeans” pulled from the pouch of a dead mother found at a nearby caravan park. Only one survived.

“They were see-through,” she says. “You could see their hearts beating. From then there was no chance we would ever lose our love for this species.”

This article by Graham Readfearn was first published by The Guardian on 6 January 2022. Lead Image: The mahogany is the most threatened of Ausralia’s seven gliding possum-like marsupials. Photograph: Daryl Dickson.

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