Ecologists from the University of South Australia and the Kangaroo Island Research Station have revealed a surprising new behaviour in the endangered Kangaroo Island dunnart: this tiny carnivorous marsupial is spending time in tree hollows. Until now the species was thought to dwell solely on the ground. The discovery highlights how little is still known about its ecology and points to fresh directions for conservation. (Mirage News)
Between 2022 and 2025 the research team recorded three separate occasions in which a dunnart was found resting in a wooden nest-box originally placed for pygmy possums, mounted some metres above ground in a mallee eucalypt tree on a property in Karatta, western Kangaroo Island. (Mirage News)
Arboreal behaviour changes our view of an endangered species
Until recently, the Kangaroo Island dunnart was presumed to be entirely ground-based, sheltering under logs, in leaf litter or in underground burrows. But the new evidence demonstrates tree-climbing capability and use of hollows. One observation noted the dunnart lying on a bed of finely shredded wood—likely nest material it had gathered itself. (Mirage News)
This finding has several implications:
- It expands the known habitat options of the species, meaning conservation plans should account for tree hollows and arboreal shelters, not just ground-cover.
- It signals the species may be more adaptable than thought—but also perhaps more vulnerable in unexpected ways (competition for hollows, predation from above ground).
- It reminds us how catastrophically the 2019-20 “Black Summer” fires impacted this species: those fires destroyed around 98 % of their known habitat. (Mirage News)
From a practical standpoint, land-managers and conservation practitioners should now incorporate monitoring programs in trees as well as on the ground. Nest-boxes installed for other species may double as detection tools for the dunnart. Volunteers and citizen scientists have a role to play.
Insights for conservation and habitat management
- Install nest-boxes in mallee eucalypts at varying heights and monitor usage — as this project has demonstrated.
- Survey tree hollows in fire-regenerated and mature woodland to identify potential refuges for the dunnart.
- Incorporate arboreal predation risk (including from feral cats or birds) into risk assessments.
- Maintain structural connectivity—the ability to climb implies that isolated ground-patches may be less adequate than thought if arboreal routes or hollows are absent.
- Use this new behaviour to boost community engagement—citizen science that includes nest-box monitoring in trees may raise awareness and generate valuable data.
Overall, this shift in understanding has tangible value: better-targeted interventions, improved monitoring, and potentially enhanced chances of survival for a species on the brink.
How the discovery came about
The finding is part of the larger Kangaroo Island Nest Box Project — a citizen science collaboration involving UniSA scientists, the Kangaroo Island Research Station, local landholders and volunteers. After the 2019-20 fires, more than 400 pygmy-possum boxes and 350 bat boxes were deployed across the island to assist wildlife recovery and to gather nesting-ecology information. (Mirage News)
Key milestones include:
- Nest-boxes installed in mallee trees on private properties in the Karatta region, western Kangaroo Island.
- Observations between 2022 and 2025 of dunnarts using the boxes. (Mirage News)
- Publication of formal evidence in the journal Pacific Conservation Biology under the title “Endangered Kangaroo Island dunnarts are partially arboreal and use pygmy-possum nest boxes”. (CSIRO Publishing)
It is noteworthy that the nest-boxes were not designed for the dunnart—yet they have proven effective detection tools. This serendipitous result invites a broader strategy: using multi-purpose nest-boxes to monitor several species simultaneously.
Additionally, the study warns that artificial hollows can bring new risks: increased predation, competition for space with other species, and possibly exposure to fire or other hazards that natural hollows might avoid. (Mirage News)
Summary of key data
| Item | Detail |
|---|---|
| Species | Kangaroo Island dunnart (Sminthopsis aitkeni) |
| Location of sightings | Karatta region, western Kangaroo Island |
| Type of structure used | Pygmy-possum nest boxes mounted high in mallee eucalypts |
| Observation period | 2022–2025 (three separate sightings) |
| Prior assumption | Ground-dwelling only |
| New interpretation | Partially arboreal; uses tree hollows and nest-boxes |
| Key risk factors | Post-fire habitat loss, predation, competition for hollows |
| Reference publication | Pacific Conservation Biology (DOI information available) |
This becomes a paradigm shift for the species: acknowledging tree use effectively broadens the habitat register and opens up new avenues for recovery actions.
What this means for the future of the species
The discovery arrives at a critical time. The Kangaroo Island dunnart is listed as endangered under Australian law and also featured as critically endangered in various listings. (Landscape SA) Before the 2019-20 fires, populations were estimated at under 500 individuals; post-fires, the situation became acute. (Wikipedia)
This new evidence means:
- Habitat restoration: Replanting or preserving mallee eucalypt stands that support tree hollows should be a priority.
- Fire-management regimes: Given tree hollows may shelter vulnerable animals, ensuring refugia survive fire or are quickly replaced is vital. (CSIRO Publishing)
- Monitoring and detection: Incorporating tree-based nest boxes and camera traps increases detection chances; knowledge gaps on arboreal use are now closing.
- Landholder cooperation: Private lands rather than just national parks (western Kangaroo Island includes private properties) are relevant.
- Predator & competition control: Because arboreal hollows may introduce competition (with possums, bats) or predation (by birds of prey, climbing predators), management must adapt.
It is fair to say that while the outlook remains challenging, especially given the small range and legacy of habitat destruction, this discovery offers a promising new dimension to recovery work.
Action-points for stakeholders
- Private landowners on Kangaroo Island should consider installing and monitoring nest-boxes at height in appropriate vegetation.
- Conservation bodies should update recovery plans for the dunnart to include tree-hollow habitats, not just ground shelters.
- Funding bodies might target tree-based monitoring and regeneration of hollow-bearing trees as part of grants or programs.
- Volunteer and citizen science groups can be engaged to monitor nest-boxes and report dunnart sightings, helping fill data gaps.
- Fire-management agencies should identify and protect refugia in trees and hollows, ensuring these features survive or are restored after fire events.
In short, this discovery reshapes both our scientific understanding and our practical response to conserving one of Australia’s rarest mammals.
Trending FAQ
Q: What makes tree hollows important for the Kangaroo Island dunnart?
A: Tree hollows provide elevated and enclosed shelter, potentially offering protection from ground predators and fire. The new finding shows that the dunnart uses elevated nest-boxes in mallee trees, indicating tree-based refuges play a meaningful role.
Q: Can nest-boxes be used for monitoring this species?
A: Yes — the recent study found the dunnart resting in nest-boxes originally placed for pygmy possums. As such, nest-boxes installed at height can function as detection tools and may form part of a regular monitoring protocol.
Q: Does this discovery mean the species is safe?
A: Not yet. Although the new behaviour adds opportunity, the species remains highly vulnerable due to habitat loss, predation, competition and fire. The discovery simply expands options for conservation; it doesn’t remove the fundamental threats.
Q: Should land-managers prioritise tree preservation now?
A: Absolutely. Preserving or regenerating trees that can form hollows, installing artificial hollows or nest-boxes, and protecting them from fire and competition should be integrated into management plans.
Q: How can the public help?
A: Volunteers on Kangaroo Island and elsewhere can: assist with nest-box installation and monitoring; contribute to citizen science programs; report sightings of dunnarts in tree hollows; and support land-management efforts to restore habitat and remove invasive predators.
Q: What is the next research step?
A: Further work will focus on how frequently the dunnart uses arboreal shelters, what tree-hollow types are preferred, how competition or predation plays out in trees, and how fire regimes affect hollow availability. Monitoring tree-based hollows across burnt and unburnt landscapes will be key.
Conclusion
The revelation that the Kangaroo Island dunnart climbs into trees and uses nest-boxes is a landmark in its conservation story. It challenges prior assumptions, opens up new habitat possibilities, and prompts a recalibration of where efforts should go. By combining ground-based and arboreal strategies, conservationists and landholders now have a richer playbook to aid one of Australia’s most endangered marsupials. With action and collaboration, the hope is that this little creature will have a stronger chance to persist in the rugged, fire-scarred landscapes of Kangaroo Island.
