It is not always easy for me to convince people that what we are doing is hard work. Our island site is warm and pleasant at this time of year, surrounded by beautiful ocean and inhabited by wonderful koalas. Fortunately, I am having many visitors to my study site, which means I have many more hands on deck, which means we can do even more!
Last month it was Geoff Pye, D.V.M., and Brian Opitz from the San Diego Zoo who helped with catching, collaring, and (most importantly) taking X rays of all the koalas. This month I had Jen and Jen from the San Diego Zoo and the San Diego Zoo Institute for Conservation Research on board, and we worked just as hard. Jen Tobey is a specialist studying the sounds koalas make (see her post Koala Field Project: Meet Jackaroo); Jen Roesler is a keeper at the Zoo who is also an expert in handling koalas, so I expected big things from this pair.
Professor Paul Roe from Queensland University of Technology, who has designed and built the sensor network that eavesdrops on our koalas, and Ben Charlton, an expert in animal communication who has recently turned his skilled hands to koalas, joined us on St. Bees. Rounding out the team was Dr. Sean FitzGibbon, an expert in koala ecology, capture, and handling, with whom I spend a lot of my time in the field.
Our target for this trip was to record the bellows of as many male koalas as we could find so that we could compare the features of each male’s bellows to his size, age, and behavior. We had three microphones and spent every night sitting under the trees of the koalas or running through the bush following their bellows. By day, we tracked the animals, checked on their position so that we knew where to go at night, and caught any new animals that we hadn’t found. We removed the GPS collars that we had deployed in September and also removed some standard vhf collars from animals that we are not going to follow this summer. We were pushed for time, so we even went catching at night, which made for extra-long days.
Luckily, we found several of the females we had caught in September that now had joeys on their backs (many of these were still in the pouch on our last trip). Little Pickle is now a fully fledged mother, and she resides up near Elizabeth, the oldest mother we are tracking. Both of these koalas are raising healthy and good-looking babies this year: Pickle’s baby is named Onion (not my choice of name), and Elizabeth is raising baby number nine, Ginger. We also found some new males; we managed to record the bellows from two of them (Eddie and Jeremy).
It was an exciting and tiring trip, with everyone’s sleep routine totally wrecked by the end. We recorded more koalas that I thought we would, we recovered all the collars we needed to (including Leaper’s, who had crossed the island!) and we even saw two males fighting one afternoon.
We are now starting to put the pieces of the koala–bellowing jigsaw puzzle together. We know that not all the males bellow all the time, but we are not 100-percent sure what makes them decide when it is their turn. We also found bellowing to be concentrated in parts of the island and absent elsewhere, making us wonder whether the males really call to attract the females or whether the females attract the males, who then bellow.
I am sure that as we plan our next trip, we are a step closer to understanding this interesting behavior in koalas; but in the meantime, I am catching up on sleep. Luckily for me, unlike my visitors from the Zoo and the Institute for Conservation Research, I didn’t have an 18-hour plane flight back to San Diego to look forward to when I returned from the island. There are some advantages to living close to your study animals!
Bill Ellis is the Clarke Endowed Postdoctoral Researcher for the San Diego Zoo Institute for Conservation.