From the field: Studying endangered northern quolls on Groote Eylandt

- by Rebecca Wheatley

It's a new year, which means there's new research to be done as I delve into my PhD. But before I start writing about that, I want to write about a somewhat related experience I was lucky enough to have last year.

In August/September, I got to join my labmates Ami, Jaime and Gwen up on Groote Eylandt, which is a large island off the coast of the Northern Territory owned and run by the Anindilyakwa people. The reason:

to help them out with their research on the endangered Northern Quoll (Dasyurus hallucatus).

Catwoman, a pretty little female Northern Quoll (Dasyurus hallucatus). 

Now, if you’ve ever been to Australia, you probably have heard the story of the Cane Toad (Rhinella marina) – even if it’s just via one of the many delightful novelty souvenirs available in Australian tourist shops.

A classy addition to any accessory collection. Image credit: Wikimedia Commons. 

The cane toad is an extremely successful invasive species that was introduced into Australia in 1935 to eat a beetle that was negatively affecting the cane industry (which it didn’t), and since then it has spread down the East coast and across the Northern Territory, and is slowly making its way down the West coast as well. One of the reasons Groote Eylandt is so amazing is because it is one of the few areas up North that has remained cane toad-free. Because of this exclusion, it is the last stronghold population of the endangered Northern Quoll, whose numbers have been decimated via their predation on this toxic species. This makes Groote an ideal location to study the quoll in its natural habitat, as numbers are high enough for recapture studies to generate useful amounts of data.

A magical sunset in the bush next to the highway to Umbakumba.

I was on Groote Eylandt for 5 weeks helping Ami with data collection for her PhD project. As well as stunning landscapes and amazing native animals, Groote Eylandt is also home to a large manganese mine. All animals need some amount of manganese to function, but like any heavy metal it can be toxic in high concentrations. For her PhD, Ami is looking at how quolls from different parts of the island (that have been exposed to different amounts of manganese) perform in motor control and cognitive function tests. We are lucky enough to have access to laboratory facilities at the Anindilyakwa Land and Sea Ranger Station, where we get to work with the Rangers to figure out how to do our research in a way that is compatible with indigenous culture.

Ami measuring one of our little darlings. 

We went out every night and set 30-60 traps in one of our three trapping areas various distances from the manganese mine, which we then checked first thing the next morning. If we were lucky, we’d see white spots and hear some angry growling – otherwise it was rather likely that we’d caught one of the other marsupials that populate the area. We then transported our precious bundles back to the lab at the Anindilyakwa Ranger Station where we sexed them, weighed them, took various morphological measures and a hair sample (to get their internal manganese concentration from) and pit- and ear-tagged them.

Alfred, a feisty (and adorable) little male. 

Lastly, we’d gather information on their level of motor control. I won’t give away too many details, but we basically assessed their performance at various speeds and analysed how many mistakes they made depending on the difficulty of the task and the speed at which they performed it. We would expect that as speed and/or “difficulty” of the task increases, the quolls will make more mistakes. The reasons for this are very intuitive and you will probably have observed them in your own life; as you do things faster you have less control over your movements and are more likely to make an error. Similarly, if a task is difficult, you’re more likely to make a mistake than if it’s relatively easy. What Ami wants to know is whether the manganese concentration the quoll has been exposed to enhances this effect – i.e., whether high manganese concentrations affect motor control.

Back to the bush you go. 

Ami also wants to look at whether manganese concentration affects cognitive function in the quolls – but that’s for her to write about! She’ll continue to run these experiments for the next two years, and hopefully get some excellent results. I was very lucky to be involved in helping out with this project, as many of the techniques she used will be helpful in my own PhD.

Having a sniff out of the corner of his bag. 

Although quolls were the main attraction for us, Groote Eylandt has plenty of other amazing qualities that made my trip there one of the most memorable ventures into the field that I’ve ever had. We are extremely privileged to be able to conduct research there, and I learned more about indigenous culture than I ever thought I would. I also saw loads of awesome animals and plants, and got to spend a lot of time in the field – which is definitely one of the best ways to spend it.

A Mertens' Water Monitor (Varanus mertensi) chilling by Milyerrngmurramaja (the "Naked Pools"). These guys are also threatened by ingestion of the cane toads. 

A Striated Pardalote (Pardalotus striatus) that was nesting next to the Anindilyakwa Ranger Station.

A Burton's Legless Lizard (Lialis burtonis) we found while we were setting traps near Alyangula.

A Helmeted Friarbird (Philemon buceroides) next to the highway to Umbakumba. 

I’d like to say a huge thank-you to my lab for this opportunity, but most especially to Ami, Jaime and Gwen for teaching me so many new skills and being the best bush-buddies ever. I’m looking forward to future adventures with the Wilson Performance Lab as I start my PhD on another kind of carnivorous marsupial… the Yellow-footed Antechinus (Antechinus flavipes)!

Sunset on the beach at Ayangkwa ("Tasman Point"). 

All images by Rebecca Wheatley unless otherwise credited.