Testing a simple solution to over-abundance

Kimberley Solly - Tuesday, December 20, 2016

This study not only looked at the number of Burrowing Bettongs to leave the Arid Recovery Reserve but also the number of bettongs investigating the gates, the influence of gate placement, how to optimise gate use via a food lure, the sex ratio of departing bettongs and also the distance travelled by a bettong to access the gate. Bettongs were cage trapped as they exited the gate to see if there was a bias in the animals that were using the gates. Also, radio collars were affixed to some bettongs before releasing them back into the Reserve in order to record the distance a bettong travelled to access a gate from their home territory.  

Baiting the gates with peanut butter and oats as well as the landform placement (swale vs dune) both had effects on the use of the gates by the bettongs. Baiting increased the visits to the gate as well as the exits from the gate. Additionally, placing gates in dunes or corners of the fence rather than on interdunal swales also increased the visits to the gates. There was no difference in the number of males or females using the gates to exit the Reserve. The movements from the gate to the bettong’s burrow were wide ranging between 75m and 1.5km with an average of 418m. 


a) Curious bettongs investigating a one-way gate b) A bettong entering a one-way gate c) A bettong exiting on the other side. Photo Credit: Kate Butler

The optimal configuration for a gate was to be installed on a dune and baited with peanut butter and oats. In this configuration approximately one bettong, on average, exited per gate per night. No incursions by bettongs or feral animals into the Reserve through the one-way gates were recorded suggesting that the gates are working effectively in restricting traffic to one-way. The results presented in this study suggest that there is great potential for one-way gates to be implemented as an effective method of managing the over-abundance of Burrowing Bettongs at Arid Recovery. 

One-way gates will reduce the costs and labour involved with other management techniques such as relocation of animals and will negate the need to cull an endangered species. A combination of techniques may be needed to successfully reduce the population to a capacity that the Arid Recovery Reserve can sustain. 

Written by Kate Butler, Honours Student, The University of Adelaide

20 years of cat control: keeping threatened species safe

Admin Aridrecovery - Monday, December 19, 2016


Buoyed after another successful week of cat control, Field and Maintenance Officer John Crompton and our dedicated volunteer shooters removed 13 cats and 4 foxes in one week. Each of the cats had between 1 and 5 native mice in their stomachs, including the threatened Plains Mouse. It is sobering to think of just how many animals these cats are killing every night, but we’re glad our feral predator control is making a difference.

Our feral predator control is partly about making a safe haven around the perimeter of the Arid Recovery fence, but also helps to keep cats and foxes out of the Reserve. Our fence is designed to be cat and fox proof, but we have to ensure there are no incursions of feral animals from damage to the fence.

Our floppy-top fence design is an extremely effective deterrent. Cats that attempt to breach the fence by pouncing on the floppy top are flung to the ground. But as everyone knows, feral cats are incredibly intelligent. If given enough time, and presented with a reward as good as the defenceless native animals inside, they will instantly take advantage of any weak point.

Our fence is currently our best defence against feral animals. Photo Credit: Kimberley Solly

Just recently, the September storm that cut off power to South Australia, also blew the floppy top inwards along sections of our western boundary. Not long afterwards we found cat tracks inside the Reserve.

Over the last 19 years, a few individual cats have breeched the fence like this. Removing them has been a herculean effort. It’s one thing to remove one cat of many in an open landscape, but to seek out and remove one lone cat in a sea of native animals is something else altogether. Great care must be taken when using traps and shooting. Usually the whole Arid Recovery team and volunteer community have to hunt intensively for months on end.

So our feral predator control strategy is to remove cats before they have time to study the fence for weaknesses. To this end, we created a permanent set of cat traps along the outside perimeter of the fence. To draw cats in, we have tried every lure imaginable: fish oil, cat urine piss and sound players that make meowing sounds. These typically catch between one and fives cats per week.

On top of these permanent traps, we also have a team of dedicated volunteer shooters. Feral control not only reduces the risk of incursion, it also creates a buffer zone protecting native animals around the perimeter of the reserve.  Some volunteer shooters have removed over 50 cats and foxes for us. No doubt many of the bilbies and bettongs of Arid Recovery owe their lives to their efforts.

John Crompton our Field and Maintenance Officer patrols the fence and permanent trap sites. Photo Credit: Charmayne Cronje

Unfortunately, no matter how much cat control we do, we will never eradicate cats from this region. There will always be new cats to wander in from elsewhere; whether they are strays from towns or ferals from far far away. But thanks to the rigours and dedicated efforts of staff and volunteers, we have at least kept their numbers lower than they would have been otherwise around the fence.

Our trapping and shooting efforts are not about hating cats and foxes, but about loving our native wildlife and doing everything possible to keep their populations strong. Please support our work managing the threat of feral cats at Arid Recovery. There are many ways you can get involved: you can volunteer, become a Friend of Arid Recovery, come out on a spotlighting tour, join one of our community events or support our work by donating or adopting a bettong or bilby.

Written By Hugh McGregor, in partnership with the University of Tasmania and National Environment Science Programme. 




Seed Predation Paradigm Shifts in Australia

Admin Aridrecovery - Monday, November 14, 2016

Animals which specialise in eating seeds are known as seed predators. In the desert, their preferences for specific species of seeds can change the number and types of plants in an area by removing seeds from the bank they grow from.

In many countries mammals are the main seed predators, followed by ants then birds. In Australia, ants are considered the most important seed predators, and mammals are considered unimportant. The role of Australian mammals as seed predators is largely unknown because they were lost before we understood how they interacted with seeds, plants and soils. Our understanding of seed predation in Australia was therefore built in areas which are devoid of native mammals.

Now these mammals, once common around Australia, are only present in places like small islands or in secure fenced reserves. The recent establishment of strong populations in fenced reserves provides the opportunity to question their role as seed predators.

At the same time that native mammals declined, Australian desert landscapes became dominated by weedy shrub species and grasslands declined. This phenomenon, known as shrub encroachment, is a symptom of land degradation. There is no known seed predator for weedy shrub species, although they mostly grow in areas that lack mammals.


Shrub encroachment. On the right hand side of this fence you can see many more shrubs. On the left side, much more grass (grey patches). Interestingly, we find lots of small mammals on the left, but none on the right.

I studied seed predation in native mammal reserves, including Arid Recovery, to determine if Australian mammals are important seed predators, especially of weedy shrub species. I placed trays of weedy shrub seeds inside reserves where mammals are common and outside where mammals are rare. After two days I counted the number of seeds left in the trays. I used tracks at the trays and photos taken by motion sensing cameras to determine which animals were eating the seeds.

Native mammals were the main predators of weedy shrub seeds and ate many more seeds than ants. The main seed predators inside the reserves were native hopping mice and the Burrowing Bettong, a small rabbit-sized marsupial closely related to kangaroos. 


A burrowing bettong (Bettongia lesueur). Burrowing bettongs were once common on the mainland and are now only found in fenced reserves or small islands. Photo credit Nick Tong.

My research indicates that paradigms on seed predation in Australia should be reconsidered to include mammals. I found that native mammals are important seed predators in Australia, and their decline may have contributed to shrub encroachment. This research demonstrates that projects aimed at restoring Australian native mammals may provide unexpected benefits such as natural weed control.

Written by Charlotte Mills, PhD candidate, Centre for Ecosystem Science, UNSW.

Know thy enemy - What happens when you breed animals in an environment where there are no predators?

Admin Aridrecovery - Tuesday, October 18, 2016

There have been a few blogs along the way regarding my research of the Greater Bilby (Macrotis lagotis) at Arid Recovery (refresh your mind here, here and here). But as they say all good things must come to an end. Time certainly does go too quickly when you are having fun doing field work at Arid Recovery, especially when you are working with unique animals like the bilby. Two and half years ago I embarked on an amazing adventure that took me all the way from the yellow sands of Bondi Beach, Sydney, to the red desert of Roxby Downs, South Australia. As soon as I heard that there was a PhD project investigating the prey naïveté of Australian native mammals, like the bilby, I knew I had to be a part of it!


Figure 1: The Greater Bilby Photo credit: Lisa Steindler

Prior to European settlement the bilby was found over 70% of Australia. Unfortunately, today they are considered legally extinct in the wild in South Australia, New South Wales and Victoria. The biggest identified threat and cause for this decline has been the introduction of exotic predators, such as the red fox and feral cat.

Thanks to the amazing work by organisations, such as Arid Recovery, feral free reserves have been established. The bilby population at Arid Recovery has boomed within this ‘safe haven’ for reintroduced species. But what happens when you breed animals in an environment where there are no predators? Do they lose all recognition of predators? Can we release them outside the fence where there ARE feral cats, red foxes and dingoes? Like many others we want to see Australian mammals beyond the fence and back in the wild and my PhD research is a step in that direction.

Now onto some basic theory behind that term “prey naïveté”, what exactly does it mean?!  If a prey animal is able to recognise a predator, they may be able to decrease their chances of being eaten. This is often known as an ‘anti-predator’ response. Whether a prey animal is able to recognise a predator may be influenced by their lifetime experiences. Animals may learn through personal experience whether another animal is a friend or an enemy who wants to eat them. Sometimes prey may not be exposed to predators within their lifetime, but they are still able to recognise and respond to them (i.e. in the case of animals living within the Arid Recovery Reserve). Animals that have lived with a particular predator for hundreds and even thousands of years may have “hard wired” responses to this predator. On the other hand, sometimes isolation from all predators over an animal’s lifetime or over hundreds to thousands of years can lead to the loss of all ‘anti-predator’ behaviours – “prey naïveté”.  

Understanding if prey are able to recognise and respond to a predator is important.

Theories on prey predator discrimination and recognition are divided as to whether prey species’ ability to recognise and avoid predators is proportionate to the duration of evolutionary exposure to specific predators or is a result of more generalised discrimination processes. Moreover, the understanding of the timeframes necessary for prey species to maintain or acquire appropriate responses to introduced predators is poorly understood. To be able to answer the question of how we can teach our native animals to be more aware of introduced predators we first need to understand what their current level of understanding is.

I attached radio transmitters to 18 bilbies at Arid Recovery so that each day I could radio-track sleeping bilbies to their burrows. Faecal samples from cats, dogs and rabbits were placed on the outside of bilby burrows to see how they would respond, as bilbies often use their strong sense of smell to recognise predators. Remote cameras were used to film the response of bilbies to the olfactory cue as they emerged from their burrow. The idea was that bilbies had to decide whether it was safe enough to exit the burrows when the faeces were present. If they recognised the faeces as a threat, then they should be more hesitant to leave the burrow compared to when they did not recognise it as a threat.


Figure 2: I radiotracked 18 bilbies for three months with the help of wonderful volunteers.                 Photo credit: Lisa Steindler

Figure 3: Camera traps were used to film bilby emergence behaviour. Photo credit: Lisa Steindler

Video analysis of burrow emergence behaviour determined that bilbies were indeed more hesitant to leave the burrow when certain predator scent was present. Bilbies spent more time only partially emerged (with at most head and shoulders out) as opposed to fully emerged (standing quadrupedally or bi-pedally, fully emerged from burrow) from their burrows when dog faeces were present, in comparison to faeces of cats, rabbits and an unscented control. The Greater Bilby has shared over 3000 years of co-evolutionary history with dogs but less than 200 years with cats. The ability of prey species to respond to the odours of predators relates to their period of coexistence. The longer that you have known your predator over evolutionary time may influence whether you can recognise their odour, even if you aren’t currently living with them.



Figure 4 and 5: What was classified as a partially emerged bilby vs a fully emerged bilby.            Photo credit: Lisa Steindler

This research is only the starting point to seeing a future for bilbies beyond the fence. This research would suggest that despite at least 15 years of isolation from placental predators, bilbies retain some level of “hard wired” recognition of their historical predators (dingoes). The next question will be: Can they survive predation attempts by these predators? Can we teach them to be a bit more aware of introduced predators such as cats and foxes? And can adapt to live in a changing world outside the fence where these predators now exist?

Thanks to all the wonderful support from my supervisors, Arid Recovery staff, and volunteers along the way, I have had an amazing PhD journey that has led to many moments of blood, sweat and tears, a growing family of wonderful friends and precious memories of a unique, charismatic animal ... the bilby!!

Written by Lisa Steindler, PhD candidate with the UNSW. 


Prey switching - What will happen when the second strain of calicivirus hits?

Admin Aridrecovery - Monday, September 19, 2016

I am about to start a project here at Arid Recovery that will study how a new strain of a virus used to control rabbit numbers will affect the ecosystem here. What will a drop in rabbit numbers do to the population of cats and foxes, as well as our threatened native species?

The original strain of calicivirus is arguably Australia’s most successful biological control method – it had huge impact on rabbits, which have caused untold ecological damage across the country. When the virus was released in 1997, rabbits went from plague proportions to scarce in a matter of weeks.

Rabbits fighting back

Rabbit numbers have been slowly recovering since as they have been evolving immunity to the virus, but it is still out there doing its job such that rabbit numbers have never quite recovered to pre-1997 levels. The removal of so many rabbits from the landscape in a short space of time had a huge impact across the whole ecosystem.

Predators turn on the natives

Rabbit impacts have been studied in detail around Roxby Downs over the last 30 years - check this paper out! When the first calicivirus came through, the population rabbit numbers crashed to virtually nothing. This had major flow-on effects. With fewer rabbits, cats and foxes lost their main food source so not only did their populations plummet, but they also became a lot hungrier and turned to eating more native animals in a process known as prey switching (analyses found a greater proportion of native animals in fox and cat scats after calici).

This put extra pressure on many native species, and it is possible a population of rock-wallabies went extinct as a result (follow up here). In the long term however, the knockdown of rabbits appeared to have some incredible benefits. Cat and fox numbers fell and have stayed down since calici, and over the 20 years since many native animals have rebounded in South Australia including dusky hopping-mouse, plains mouse and the crest-tailed mulgara (read more here).

A new strain of virus is coming

There is a new strain of calicivirus on its way to Roxby, to which most rabbits here are yet to evolve any immunity. My project will look at how native prey species will be affected by controlling rabbit numbers with this new strain of the virus. I will be comparing the extent to which cats and foxes switch from hunting rabbits to killing native species, versus how much the populations of feral predator will fall or rise.

We have a perfect opportunity to test this near Roxby Downs in 2016/2017 as the new strain of calicivirus becomes established in the area. This new strain (RHDV2) is an altered form of the original, and has been killing many rabbits that are resistant to the original strain.

Originating in Canberra, it has moved across south-east Australia in a wave and is currently in the Flinders Ranges. It will create a neat before and after experiment. I will use the Arid Recovery Dingo Pen as a contained area where we can track exact numbers of cats, rabbits and native animals as the drama unfolds.

Cats with cameras

By tracking numbers and locations of native animals I can make a detailed analysis of exactly what happens when rabbit numbers crash. I will measure the extent of prey switching to find out how many more native animals are killed by cats after rabbit numbers fall.

To do this, I will need to follow cats on their daily journey of destruction. I’ve been fitting cats with video cameras to record what they hunt and how they behave, as well as using small GPS units so I can see where they go. Here is an example of one of my collared cats ready to hunt! This will enable me to measure the actual kill-rates of feral cats, and estimate the impact of their predatory behaviour on native animals before and after rabbit knockdown.

I will record the area covered by each feral cat, the number of rabbits and natives killed every 24 hours and the total number of animals killed by the whole population of cats. From this I can calculate the total predation pressure.

I may find that native animals are at their most vulnerable when rabbits decline and that during those times we should ramp up predator control. Or it might make no difference. What we learn will be useful for protecting vulnerable species that persist in refuges and for planning threatened species translocations.




Figures 2 and 3: Cats have been fitted with cameras in the Dingo Pen to observe predation and to document what occurs when the second strain of calicivirus strikes Roxby Downs. Photo credit: Hugh McGregor

Written By Hugh McGregor, in partnership with the University of Tasmania and National Environment Science Programme. 


Reference:

McGregor, H., Legge, S., Jones, M.E., and Johnson, C.N. (2015) Feral cats are better killers in open habitats, revealed by animal-borne video. PLoS ONE 10(8): e0133915. doi: 10.1371/journal.pone.0133915

Pedler, R.D., Brandle, R., Read, J.L., Southgate, R., Bird, P., and Moseby, K.E. (2016) Rabbit biocontrol and landscape-scale recovery of threatened desert mammals. Conservation Biology, 30(4), 774-782. 

Read, J., and Bowen, Z. (2001) Population dynamics, diet and aspects of the biology of feral cats and foxes in arid South Australia. Wildlife Research, 28(2), 195-203.

Bettongs learning to survive

Kimberley Solly - Friday, June 17, 2016

Followers of our blog would be familiar with the ARC linkage project with UNSW titled 'Tackling Prey Naivety' that has been in full swing at Arid Recovery. If you need a refresher why not check out these blogs: Spot our newest members of the Arid Recovery family, How the tricky stickies got their name - How to catch a rat!, Quoll-ity time at Arid Recovery, Bettongs behaving...badly?

The project recently had a feature in the Sunday Mail and Herald Sun







Bettongs behaving...badly?

Admin Aridrecovery - Thursday, February 04, 2016

As I mentioned in my last post, the University of New South Wales (UNSW) and Arid Recovery (AR) have teamed together to explore and potentially improve anti-predator responses in threatened species on the Reserve. Reintroductions of these native species often fail due to a lack of effective anti-predator responses (Moseby et al. 2011). The anti-predator responses of threatened species may improve by exposing them to low predation pressure (four cats and two Western Quolls), allowing for successful reintroductions outside the AR Reserve.

 

Do you think Sepia (Western Quoll) could pass as a terrifying predator? Credit: Kimberley Solly


As well as taxidermy cats (as above), there are FOUR feral cats scaring bettongs in RLX. Credit: Lisa Steindler

I’ve been involved with many facets of this project during my time at AR. One of my favourite parts is determining approach distances for collared bettongs, which helps establish how aware bettongs are of potential predators and indicates something about an individual’s behavior. The concept is simple. Imagine you’re a bettong who’s never been exposed to a feral cat before. A naive bettong wouldn’t be aware of a predator approaching and therefore would be an easy target. However, if you had been exposed to cats and perhaps even survived an attack by one you would be more wary and harder to approach. This would improve your anti-predator response, making you harder to eat and increasing your chances of reproductive success. We want to know if this process is happening. Therefore we preformed approach distance experiments on bettongs in expansions without predators and compared them to the approach distances of bettongs in Red Lake and the Northern where there are predators.

 

Determining a bettong’s approach distance requires a strong head torch and stellar radio tracking skills. Bettongs are nocturnal so can only be approached at night. A normal experiment goes as follows. One, drive to a bettong warren where you know a collared bettong lives, attempting to avoid lizards, hopping mice, and other bettongs and bilbies on the road. Two, get your tracking gear out, turn the gain all the way up on the receiver and flip the yagi antenna vertically, listening for a telltale beep that will indicate that the collared individual you’re tracking is nearby. Three, if you’re close enough flip the yagi horizontally and turn the gain down. This is when the fun begins.

 

I watched Bec’s headlamp bob in the distance, blinking like a distant lighthouse when she walked up and over a sand dune. “Ok channel 17, you’re mine.” I headed straight towards the loudest blip I could hear from the receiver. As I walked I swiveled the yagi from left to right correcting my path to always head towards the loudest beep. That meant I was heading towards the collared animal. I struggled up and over a sand dune, trying not to trip on acacia bushes or fall into a bone-dry mulga tree. As I came over the crest of the dune the beep got even louder, becoming distorted. I turned the gain down and kept moving forward.

 

As you get closer and closer to the individual it’s important to be constantly adjusting the gain and your direction. You can make more sensitive directional corrections with a low gain, but turn it down too far and you won’t be able to hear the collar anymore.

 

I heard a farting noise and saw a bettong sprint out from under a saltbush. I had reached the gibber plain in between two dunes. I noticed that bettong didn’t have a collar, but based on the loudness of the beep I knew I must have been getting close. After about 10 meters I looked slightly to my left and saw a pair of shining eyes crouching under a bluebush. “Gotcha,” I muttered under my breath. This bettong did have a collar. He looked at me, slowly hopped out from under the bush and then took off towards my left. The beep became softer as he ran off, so I knew he was the collared individual I had been tracking. I paced out 12 meters from my position to the bush I initially saw him under. My first bettong approach distance, done!

 

Gotcha! This bettong was trapped and measured but didn't want to leave the bag. Credit: Evan Griffith

You read that right, bettongs fart. And no we’re not talking about flatulence. It’s actually their alarm call, however, it can be very handy to scientists working in the outback. When in doubt, blame it on the bettongs! Occasionally, you’ll be tracking a bettong and the beep will get louder and louder and then fade. This usually indicates the animal is running away from you before you get close enough to see it. The first couple times this happens we follow it again, but after the third time we stop. If you kept going you might walk across the entire Reserve and never see the collared individual! Not seeing the bettong after three approaches is a very interesting result that indicates that they may have a heightened awareness of potential threats.

 

Even though approach distance experiments can run late into the night I enjoyed every session. Since most outback animals are nocturnal you really can’t get a feel for just how much life there is on the Reserve until you go out at night. From nightjars to geckos, western brown snakes to the stick-nest rats, biblies and bettongs, it is never quiet. Standing on top of a dune, bathed in moonlight and watching the reflection of hundreds of eyes is an experience that should not be missed. 


Written by Evan Griffith, ARC and Arid Recovery intern


Bon Bon Bonanza

Admin Aridrecovery - Thursday, January 21, 2016

The Roxby Downs Green Army works mostly in partnership with the Arid Recovery Reserve, but under the South Australian Rangelands Alliance shared between Arid Recovery and Bush Heritage, the opportunity came along in early December for the Green Army to undertake a placement at Bon Bon Reserve. Bon Bon Reserve, which is 150 km west of Roxby Downs (on the Stuart Highway), is a de-stocked sheep property (over 2000 km2 in size) acquired by Bush Heritage in 2008, and is run by managers Mike Chuk and Julia Harris as a protected area, wildlife corridor and refuge.

The Green Army team studied under and assisted Mike and Julia with a number of tasks. This included maintenance on the original boundary fence with neighbouring station Mount Vivian. Restoring this historic fence was simple but labour intensive. The team assisted Mike and Julia to drive 6ft star droppers alongside the original mulga fence posts to straighten and provide extra stability. The team twitched the original and new posts together with fencing wire to ensure the two didn’t become separated over time.


Using our strength to straighten the property boundary fence.

Time was also spent upgrading the existing fire breaks and access tracks. This provides a navigable route (which is smooth and obstruction free) for fire appliances to access parts of the Reserve from the Stuart Highway. Over time, woody plant species such as Acacia and Senna have established on the track, and required removal by hand and in some cases chemical treatment to prevent re-sprouting.

Grading this track involved a contraption built from old railway line and four truck tyres. The contraption was chained to the back of a tractor and pulled along the dirt track. The railway line would flatten and compact the surface and the tyres would catch and push any debris that may be left on the road such as sticks and rocks. The team assisted by helping manoeuvre and attach the bulky grading device around difficult obstacles and on and off the back of a flat-bed ute for transportation.


Loading the tyres and the railway line for transportation was a creative process that required the use of the tractor to prevent serious strain or injury.


Shovelling a sand bund to allow access by the grading device.

We also spent time locating and managing rabbit warrens in an area of the Reserve, where priority control was identified. The Managers have a responsibility to monitor and control both plant and animal pest species. Smaller warren entrances were simply filled in, while larger entrances were treated chemically. On inspection of some previously recorded warrens in hard calcrete country near the edge of a small salt lake, some of the warrens seemed to be getting larger and there were obvious new tracks and scats present. Southern hairy-nosed wombats had moved in and were increasing in activity, further extending their known range on the Reserve, which thrilled everyone involved.


Preparing a rabbit warren for treatment.

An active wombat burrow.

We participated in a range of other tasks including seed collection, visiting historic photo points to see how some areas had changed over time, and assisting University students who were conducting biological surveys using pit fall trap lines in the south of the Reserve.


An opportunity to brush up on plant ID skills.

Working on Bon Bon Reserve was a great opportunity for the Green Army team, and Mike and Julia were grateful for the assistance, achieving goals that would have been nearly impossible without a little help. We thank them for their hospitality and look forward to visiting again someday.

Do you want to gain field experience across a variety of activities? The next Green Army project starts in March. Anyone who is interested can contact B0210002202G@cva.org.au or visit www.conservationvolunteers.com.au/greenarmy.


Written by Tegan Elms, Green Army participant

Quoll-ity time at Arid Recovery

Admin Aridrecovery - Friday, January 15, 2016

My name is Evan Griffith. I recently graduated from Grinnell College in Iowa with a bachelor’s degree in biology. I’ve been at Arid Recovery (AR) for seven weeks now, working as a research assistant with Dr. Rebecca West (Bec), a research officer for the University of New South Wales, who is one of AR’s research partners. Since arriving in the outback I’ve trapped bettongs, bilbies, and bandicoots, helped dig Beethoven, one of the reserve cats, out of a warren, radio tracked stick-nest rats, counted carrots at “ratstaurants,” determined approach distances of collared bettongs, scored bettong behavior videos, dragged and helped count track transects, got three flat tires on three different vehicles in one day, and observed all kinds of wildlife. Some personal highlights and favourites include seeing a bearded dragon, gibber dragon, western brown snake, sand goanna, shingleback (sleepy) lizard and of course the big four, greater bilby, burrowing bettong, greater stick-nest rat, and western barred bandicoot. Ian, a tree dtella, lives in our kitchen and has provided hours of entertainment. I find spinifex hopping mice adorable and have a slightly strange obsession with their fluffy tails. In addition, the variety and density of bird life has been a constant delight. I enjoy watching grey and pink galahs gather in the mulga trees outside my room, listening to large flocks of white-browed babblers caw at each other as they swoop between green acacia bushes on sunset red sand dunes, and observing wedge-tailed eagles float on thermals high above the landscape. However, if there is one species that has left its mark on me it has to be the Western Quoll. There are two quolls at the Reserve, Sepia and Koombana, and I have had the privilege of meeting them both.

Sepia up close. Credit: Evan Griffith

Reintroducing endangered mammals to the Australian outback is a challenging endeavor. Many reintroduction initiatives fall short due to predation by feral cats and red foxes, caused by a lack of effective anti-predator responses in native mammals (Johnson and Issac 2009; Moseby et al. 2011). Current research projects at AR are attempting to determine whether prey naivety can be reduced in threatened species by exposing native mammals to low predation pressure (look for more on this in my next blog post about bettong behavior). The idea is that if native prey naivety can be reduced reintroductions outside the reserve have a better chance for success. As part of this endeavor, Sepia and Koombana, two female Western Quolls have been brought onto the Reserve. Both quolls have been trapped regularly for health checkups and to examine their scat. Looking at quoll scat, as incredibly exciting as it sounds, allows us to determine what the quolls are eating, thereby demonstrating their impact on the native mammal populations in the Reserve. Tracking down the quolls in order to trap them isn’t always as easy as it sounds.

When I first arrived at AR I was informed we have one good quoll and one naughty quoll. Sepia is relatively easy to find in the southeastern part of the Northern Expansion (Northern). In contrast, Koombana is never in the same place. She could be in the Northern or the Second Expansion (Second). Seeing Sepia up close for the first time was an incredible experience. Quolls are beautiful, with their spotted coat, bright shining eyes and long pointed nose. Part of the appeal of quolls for me is that they’re like nothing I’ve ever seen before. They’re fierce predators, but are incredibly calm when being handled. They have sharp digging claws and a long tail. Their spots are specific to individuals and can be used to identify them. There is something intangibly attractive about them, and as soon as I saw Sepia I was completely smitten.


Evan releasing Sepia into her burrow. Credit: Bec West

Finding Koombana so that we could trap her became an intensive quest. I started out on the razor (polaris sand buggy) at 7 am and headed to the Northern where she had been seen most recently. The radio collars on the quolls have a range of between 200 to 700 meters, depending on the height of the sand dune you’re standing on and how windy it is. In order to scan the entire area I drove to the eastern border fence, chose a dune and headed west along the crest. I stopped about every 500 meters and listened for Koombana with the receiver tuned to her specific frequency. As soon as I got to the western border I turned around, chose another sand dune and headed east. After five hours with no sign of Koombana I was getting pretty hot and sticky and ready for lunch. Bec suggested that I head over to the Second since I wasn’t having any luck in the Northern. I again started slowly travelling along seemingly endless sand dunes, listening for any slight beep that would alert me to Koombana’s presence. After another two hours I finally heard something! I tracked Koombana down to a burrow about 1.5 km south of the northern border, basically in the middle of nowhere, which is classic Koombana. Bec came and helped me put a burrow trap in and two mornings later we got her! I was so excited to see another quoll and Koombana didn’t disappoint. She’s slightly larger than Sepia, but just as beautiful.


Koombana being released into one of her many burrows. Credit: Bec West

Spending eight hours on the razor in 38 ˚C was a pretty long day, but it was totally worth it to be around these incredible creatures. Recently, I got the chance to see both quolls again when we trapped them on the same day, which has never happened before! As my time at AR comes to an end I’m grateful for the opportunity to see quolls, bettongs, bilbies, and all of the native mammals of Australia. Their uniqueness and special qualities can’t be overstated. The current collaboration between UNSW and AR as well as other reintroduction efforts will hopefully contribute to the spread of these animals across their former habitat, allowing for more Australians to experience what I felt when meeting Koombana and Sepia for the first time.

Written by Evan Griffith, ARC Project intern at Arid Recovery

Bilby Tails Part II: Trials, Tribulations, Traps and Transmitters

Admin Aridrecovery - Friday, November 20, 2015

If you are a regular visitor of the Arid Recovery blog, you might have read a bit about the ‘bilby business’ that has been happening at the Reserve over the last few months. With the latest experiments on our resident transmitter-equipped bilbies wrapping up at the beginning of November, the final task of retrieving the transmitters has been on the agenda of many of the staff, students and volunteers at Arid Recovery.

For UNSW PhD student Lisa Steindler, removing the remaining tail transmitters from the last 10 of her caught Greater Bilbies (Macrotis lagotis) is just as important as putting them on. Not only are tail transmitters expensive pieces of equipment (retailing at over $200 each), they can be turned off and reused for further research at a later date. Re-catching bilbies can also provide some interesting data on how their weight and body condition has changed over time.

You may be asking “Shouldn’t it be easy to re-catch a bilby, especially if you can track where it is?” Prior to undertaking this task, I would have replied “Sure, we’ll just put a trap in the bilby’s burrow entrance, he’ll waltz on in and gladly hand over his transmitter!” After (finally) retrieving the last transmitter earlier this week, I can safely say that recapturing bilbies is not as easy as one may think. Below I have provided some short explanations of the possible scenarios that I came across during our time recapturing 10 bilbies.


Scenario 1: The tail transmitter falls off.

Transmitters recovered from bilbies: 5 (Romeo, Boomer, Bob, Betsy and Bruno)

Difficulty of retrieval: Varies from pleasantly easy when the bilby conveniently sheds the transmitter above ground on a sand dune (see figure 1), to back-breakingly difficult when it is lost metres down a burrow (see figure 2).


Figure 1: A tail transmitter left on a sand dune by Romeo. The most difficult part of retrieving this transmitter was bending down and picking it up. Credit: Lisa Steindler


Figure 2: Finding a transmitter in a burrow involves 3 steps. 1) Using the radio tracker, find the strongest signal emitting from the ground. 2) Dig, dig and dig some more. 3) Repeat as necessary until the transmitter is found. This process can take as little as 5 minutes or as long as 5 hours. Credit: Lisa Steindler


Scenario 2: The bilby is caught using a trap.

Transmitters recovered from bilbies: 4 (Bellamy, Brian, Bolt, Bullet and Bruce)

Difficulty of retrieval: Depends. The initial set-up of a pen trap can be labour intensive (figure 3), but if a bilby goes into one of the set traps on the first night, all that hard work pays off. On the other hand, trying to catch a bilby hiding in a bettong warren can prove difficult when the only animals you catch for 2 nights are Burrowing Bettongs (Bettongia leuser) and a goanna (Varanus gouldii). Once the bilby’s neighbours have been moved, trapping can be successfully achieved (see figure 4).


Figure 3:  A completed pen trap. Constructing a pen trap involves identifying the number of entrances in the warren, building a fence, complete with footnetting around said warren and wiring traps around and inside the fence. Thankfully, with the help of the Green Army, many hands make light work! Credit: Lisa Steindler


Figure 4: When a pen trap is set up around a warren, it is common to trap a neighbour or two instead of the target bilby. In this case, a Sand Goanna is being coaxed out of a trap by Green Army member Jesse. Credit: Adrian Friedel


Scenario 3: Volunteers are led along a 3-week chase by Bill, a cunning escape artist bilby.

Transmitters recovered from bilbies: 1 (Bill)

Difficulty of retrieval: I wouldn’t recommend this scenario to anyone. After 5 days of pen trapping (figure 5), over a week of rain delays, a further 3 days of failed burrow trapping (figure 6) and 1 mornings worth of digging, Bill was finally re-caught the same way he was caught (figure 7). In a net.


Figure 5: Some may think that 6 traps for one bilby might be too much. In this case, it proved to be not enough, with Bill the bilby escaping under the fence from this pen. Credit: Lisa Steindler


Figure 6: Trying a different tact. After residing in a few single-entrance burrows, we thought Bill might fall for a well-baited trap. As you can see, we were wrong. He burrowed straight under instead. Photo Credit: Sam Fischer


Figure 7: Success! After escaping a pen trap, and burrowing around several burrow traps, Bill was caught by digging behind his burrow, flushing him out and into a net. Credit: Bec West


Now, as the last removed tail transmitter is turned off, I’ve had a moment to reflect on the past few weeks. Having the opportunity to work with (arguably) one of Australia’s most iconic endangered animals has been one of the many highlights during my time volunteering with Arid Recovery. The excitement of seeing those distinctive big ears, and the satisfaction of removing the transmitter after weeks of collecting data far outweighs the many early starts, hours behind the shovel, and patience-testing moments. 


Written by Sam Fischer, Arid Recovery Volunteer and Roxby Downs Green Army Member.

Arid recovery is a conservation initiative supported by:
bhp
adelaide university