Quest for the northern quoll

High up on the rocky sandstone range of Carnarvon Station Reserve, a dozen cameras wait like silent sentinels. Activated by movement, they snap away at the furred, scaled and feathered creatures that happen by: busy little pebble mound mice, an inquisitive rock rat, slow-moving freckled monitors, dingoes and flighty bronze‑wing pigeons.

Northern quolls. Photo Lochman Transparencies.

While these images are wonderfully affirming that years of careful conservation management on Carnarvon Station is providing sanctuary for our irreplaceable native animals, the cameras are there to record the presence of a particularly rare and elusive mammal: the northern quoll.

Like many of Australia’s smaller mammals, the nationally endangered northern quoll has suffered an alarming decline in numbers over the last 200 years. Widespread habitat destruction and degradation, more frequent and hotter fires, feral predators like cats and foxes, and possibly disease, have all taken their toll. However, the northern quoll’s decline has been particularly sharp in places invaded by cane toads.

Northern quoll. Copyright Frank Woerle / AUSCAPE. All rights reserved.

About the size of a small cat, the feisty and carnivorous northern quoll eats insects, but it will also hunt the occasional frog. When a northern quoll happens across a cane toad it will normally bite the back of its neck – where the cane toad’s toxins are exuded.

The northern quoll has little or no resistance to these toxins, and populations tend to rapidly disappear in a particular area soon after cane toads arrive.

Introduced into Australia in 1935, cane toads have rapidly spread across Queensland, and more recently into the Northern Territory. They are now one of the most abundant vertebrates in northern Australia, and are found in nearly every habitat.

This means there are now only isolated places – like high up on central Queensland’s Carnarvon Range – where the northern quoll can live and safely breed in a relatively cane toad-free environment.

Murray Haseler is an Ecologist with Bush Heritage. He’s spent a good deal of his professional career working in and around the Carnarvon Range, where Carnarvon Station Reserve is located.

The cane toad is implicated in the decline of the northern quoll and many other species. Photo Cathy Zwick.

“It’s ideal habitat up there for the northern quoll: shrubby and ‘bouldery’ with plenty of cover from feral predators. It’s flat enough for water to pool, but not really enough to support any large numbers of cane toads.

“Northern quolls can survive without water most of the year, but they need good access to it during the breeding season (a synchronised two-week period usually between May and July) when the females are lactating.”

Temporary rocky pools are enough for the quolls but may not be enough for the toad. The wet years recently may have had the quolls knocked back to their highest refuges, the dry ones likely to follow now may see them gain some ground back.

It’s likely that a number of northern quoll populations are surviving on the Carnarvon Range, and one or two of them may actually be on Carnarvon Station.

During the Bush Blitz in 2014, Carnarvon Reserve Manager Chris Wilson and BHP employee Ellen Couchman set up a sensor camera, watched by Murray Haseler. Photo Alison Wilson..

“Last year on Carnarvon Station, we brought in some specially trained quoll sniffer dogs to see if they could track down breeding areas using their scent,” says Murray. “We worked them in the general area where we had the last confirmed northern quoll sighting, with positive indications, so this is where we’ve set up more cameras to get the corroborating evidence we need.”

To improve the odds of catching a northern quoll on camera, Murray has set up small ‘bait holders’ – boxes (that curious animals can’t open) filled with peanut butter, honey, oats and fish oil.

Rocky outcrops on Carnarvon are ideal habitat for the northern quoll. Photo Wayne Lawler / EcoPix.

Checking and moving the movement-activated cameras and collecting the images is a time-consuming exercise in rugged habitats scattered through high hills. The best areas are away from tracks and can only be accessed on foot. But as Murray is very keen to point out, all the effort is worth it.

“If we can confirm a breeding population up there, we’re really getting somewhere. We can start observing them and understanding what’s working for them, and what might be adversely affecting them.”

“Once we have some answers, then we can start to do something to really help them.”

Carnarvon Station Reserve was acquired in 2001 with the assistance of the Australian Government under the Natural Heritage Trust’s National Reserve System Program, and an anonymous donor.