Urban Koala Update

A wild koala with dirty-tail disease.

Hi again from Brisbane, Australia, where for the last few weeks we have been gathering in our GPS collars and releasing the koalas back into their trees (see post Urban Koalas). It has been a hectic period, because I need to have all this work finished before I head back to St. Bees Island next month, so I am happy to reveal some good news from our recent work: almost all of the koalas we tracked this winter in the urban environment had babies, and when we released them, all these joeys seemed to be doing well.

One thing that we see more in the Brisbane area than anywhere else is signs of disease, mostly “dirty tail” and conjunctivitis caused by chlamydial infections. This disease is part of the problem Southeast Queensland’s koalas must overcome if they are to survive as a viable population in the future. Chlamydial infections cause infertility and can blind koalas. In severe cases, koalas die as they become weaker and weaker with respiratory and other infections.

We have begun testing all the koalas we come across in the Brisbane area to compare with koalas at St Bees Island. We know that the St. Bees koalas are very healthy, even though chlamydia occurs on the island, so now we want to see if there is a difference in the strains of disease between the locations, or if the koalas on St. Bees are somehow better able to defend themselves against this disease. I hope our results will shed some light on how we should tackle this problem in the future.

Koalas at the San Diego Zoo look much like koalas at St. Bees Island; they are healthy, fluffy, and don’t seem to have too many worries in their world. In other places, koalas have to deal with cars, dogs, and, in some cases, their trees disappearing as new housing estates are built. So, it is not that surprising that we find more disease where koalas are under more types of pressure than where they are not. I have included a photo of one of the young females we found, and you can see that she has dirty tail. While this can be fatal to many koalas, it is not always the case, so I am hoping this koala will recover. I am happy to say that we did not find many koalas with signs of disease, and most animals were in very good condition.

In the meantime, I will be back on St. Bees, counting myself fortunate to be working on such a healthy population. Breeding season is well under way, and I am going to be joined by some researchers from the San Diego Zoo. I hope that together we can find some answers to the plight of the koalas in the southeast.

Bill Ellis is the Clark Endowed Postdoctoral Researcher for the San Diego Zoo Institute for Conservation Research. Read his previous post, Koalas and Cyclone Ului.

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