A year in the life of a koala

There is still much to learn about the elusive koala. For an animal that is so iconic and beloved, surprisingly little is known about its habits. Popular belief is that they are slow and simple creatures content to drowse up a tree all day – but is there more to their lives?

Their inherent secrecy is partly to blame. Monitoring and surveying koalas is a tricky business. High up a gum tree, individual animals can be hard to spot.

Radio tracking is a reliable way for us to learn about an individual animal’s requirements and behaviour.

Lake Innes on the midnorth coast is recognised as good koala territory, however it is under increasing pressure from development and remaining koala habitat is also at risk of fires.

The Koala Recovery Partnership, a team involving Port Macquarie Koala Hospital and other local experts, chose Lake Innes for a recent project that involved setting up 10 local wild koalas with radio trackers.

The team had the privilege of following these 10 koalas for a year, leading to a greater understanding and appreciation of these creatures. The project dispelled the myth of koalas snoozing in trees all day, showing them as animals with complex habits and needs.

The chosen koalas were five males and five females. Before being fitted with tiny, specially-designed radio collars that would track the koalas’ location they were given extensive health checks.

This helped answer initial questions about health of koalas in good habitat and gave a benchmark for their health for the duration of the study. Initial testing showed that only one male had chlamydia. This was good news, followed by despair when another male became sick with wet bottom and gunky eyes – showing that weather conditions in particular can bring disease to the surface even in good environments.

The study also looked for answers about the koalas’ home range. Radio tracking showed that dominant males have the largest habitat areas of up to 90ha, however the difference was not that significant. Females move at random around core areas – there is speculation as to whether this is to meet males, access food or escape predators. All koalas, the study showed, although solitary animals, appeared to roam their territory for feeding, breeding and social requirements. This reinforces the need to avoid habitat fragmentation which makes the animals vulnerable to vehicle and dog attacks.

While we already knew about koalas’ fussy eating habits, the study answered questions about seasonal habitat selection and how their occupancy of areas changes across the seasons. However, it also asked more questions about the best way to survey and learn about this variation, as one-off surveys can’t hope to answer everything.

As koalas are also notoriously difficult to detect in trees even when tracked to a precise location. Data relying on sightings are fraught with detection errors.

The study also indicated that trees in suburbia can be embraced in a koala’s home range. It’s lovely to think you could have a koala in your backyard but this unfortunately can lead to hazardous journeys between food trees. There is also the issue of large trees being lost to safety and further development, with virtually no replacement of habitat in urban areas.

This does not negate the need to involve large-scale landowners in creating and maintaining habitat areas adjacent to reserves and national parks. Results from the study clearly showed that as koalas follow their complex feeding and breeding habits they have zero understanding of property boundaries separating protected from potentially hazardous areas.

It is becoming increasingly apparent that a wide range of extensive and complex habitat areas is essential to the survival of individuals and colonies. This reinforces the need for koala-friendly management of our land resources.

The Koala Recovery Partnership is a joint venture between local koala experts at the Port Macquarie Koala Hospital, other local scientists with funding from the NSW Koala Strategy.

“Radio tracking is a reliable way for us to learn about an individual animal’s requirements and behaviour.”