University of South Australia and Kangaroo Island Research Station ecologists have made a remarkable discovery about the mysterious and endangered Kangaroo Island dunnart: it is partial to climbing trees.
Up until now, the small carnivorous marsupial was thought to be a ground dweller.
The finding, published this month in Pacific Conservation Biology, is the first confirmed evidence that the Kangaroo Island dunnart can climb trees and shelter in hollows, using artificial nest boxes that were originally installed for pygmy-possums.
The discovery is part of the Kangaroo Island Nest Box Project, a large-scale citizen science initiative led by UniSA scientist Associate Professor Sophie (Topa) Petit and Peter Hammond from the Kangaroo Island Research Station.
Following the catastrophic 2019-2020 bushfires that almost destroyed half the island, volunteers deployed more than 400 pygmy-possum boxes and 350 bat boxes to help wildlife recover and to better understand their nesting ecology.
"The last thing I expected to find in one of our pygmy-possum nest boxes some distance up in a mallee eucalypt was a dunnart. It was a wonderful surprise," says Peter Hammond.
Assoc Prof Pett says it's an important discovery, "not only because the ecology of this threatened species is poorly known, but also because it is evidence of yet another species using tree hollows, which are very important to biodiversity conservation."
Between 2022 and 2025, the team recorded three separate sightings of the dunnart resting in wooden pygmy-possum boxes attached to eucalyptus trees on a property in Karatta, on western Kangaroo Island.
In one instance, the dunnart was observed resting on a bed of finely shredded wood - possibly material it had collected itself to form a nest.
Many feared that the Kangaroo Island dunnarts were pushed to the brink of extinction during the Black Summer fires over 2019-2020, which destroyed 98% of their known habitat. Since then, researchers have been learning more about their behaviour, distribution, and survival strategies.
Although nest boxes provide a way of studying wildlife that shelters in trees, the study also cautions that artificial hollows can present new risks, including predation and competition for space among species sharing the same nest boxes.
The Kangaroo Island Next Box Project was a finalist for the 2024 Australian Museum Eureka Prize for Innovation in Citizen Science. It has brought together scientists, local landholders and community volunteers to build, install, and monitor hundreds of nest boxes across the island's fire-affected landscape.
"Our continuing research on the use of nest boxes will allow us to understand better the interactions of some of the species that use hollows, and the fascinating drama taking place inside our trees."
'Endangered Kangaroo Island dunnarts are partially arboreal and use pygmy-possum nest boxes' is published in Pacific Conservation Biology. DOI: https://doi.org/10.1071/PC25057
