Category: monitoring

Island life, saviour of the wrybill

I’ve never been so pleased to see the braids of a river than when I finally escaped the jaws of the Waimakariri Gorge in my kayak, as part of the Coast to Coast race. A braided river brings not just relief from roaring bluff corners, and the threat of capsizing my kayak, but a peaceful place that unusual birds decide to call home.

Rakaia River, NZ (Geoff Leeming, 2006, CC BY-NC 2.0, via flickr)

One such creature is the Wrybill or Ngutu parore. It’s the only bird in the world with a laterally curved beak (bending to the side)! Sadly, this little bird faces many threats. In 2008 some optimism was found in the research of Duncan, Hughey, Cochrane and Bind (River Modelling to better manage mammalian predator access to islands in braided rivers). The paper explained how particular characteristics of braided rivers could be used to support successful breeding of braided river birds, including our wee friend, the Wrybill.

Braided rivers are made up of multiple threads of flowing water, with islands found between the threads. The researchers knew that these islands provided a safe place for endangered breeding birds, with the water flowing around them providing a partial barrier to a major threat –

Wrybill
(57Andrew, 2007, CC BY-NC-ND 2.0, via flickr)

introduced mammalian predators, such as hedgehogs, rats, mice, stoats, weasels, ferrets and cats.

It was already known that water extraction, narrowing and stop-banking of rivers impacted the flow of water in the braids, but little was known about the optimal flow of water or the required characteristics of the islands to support breeding birds. Models were used to determine the number and area of islands needed for successful breeding. The researchers found that certain levels of water flow preserve islands large enough for nesting (larger than 2 hectares) and protect the area from mammalian predators or weed invasion. This information was used to recommend abstraction rates on braided rivers during peak breeding season. They did conclude that using photos in the research would increase understanding of how islands change in different flows.

One of the authors, Ken Hughey, was from Lincoln University and his PhD, back in 1985, looked at factors impacting the breeding of braided river birds in Canterbury. He studied five different birds: Wrybill, Banded dotterel, Black-fronted tern, Pied stilt, and the South Island pied oystercatcher. Among other things, Ken found that higher levels of predation on birds occur where there were lower flows of water and lower numbers of channels or threads in the river. He recommended that minimum flow levels should be higher during the breeding season to protect the nesting birds. The 2008 study builds on this understanding and provides information not just about the flow of water needed, but also the size of the islands required to protect the nesting birds.

This study has been used in subsequent research in New Zealand around maintaining river flows in braided rivers. This is unsurprising given braided rivers are rare around the world and Canterbury is known as New Zealand’s braided river hotspot. The themes within the research were around maintaining river flow levels, predator and weed control, maintaining river islands, and water abstraction. Advances since this work seems to be focussed on weed control and the impacts of hydropower to braided river systems.

It appears that the messages about the importance of minimum flows and island size in braided rivers for breeding birds are getting through. The Regional Council in Canterbury (ECAN) refers to the importance of flows in preserving the ecology of the river for breeding river birds in the Canterbury Water Management Strategy and the Canterbury Land and Water Regional plan. The knowledge that came from the research by Duncan, Hughey, Cochrane and Bind, and subsequent research, has clearly shown how local communities think about braided rivers and informed how they care for them. This is demonstrated by the Ashley Rakahuri River Care Group in 2022, when they made a submission to the ECAN to raise concerns about gravel extraction on the Ashley Rakahuri River and how this will impact the islands needed by birds to breed safely.

This approach also appears to complement work by the Predator Free 2050 campaign regarding pest control within braided river environments. I was intrigued as to how the authors felt the research was received and asked one of them, Ken Hughey, about the impact. He said it ultimately led to high flows being recommended and resourcing for predator control on the islands. Sounds like a great result!

New Zealand Map (mhx, 2010, CC BY-NC-ND 2.0, via Flickr)

Undertaking research consumes your life while you are doing it. It is fascinating to see the journey from conception to the completed work and then how it informs environmental work moving forward.

The Wrybill is still classed as vulnerable and there is work to be done, but this research has added valuable insight into flow regimes for braided rivers. It has highlighted the importance not just preserving islands for breeding birds, but ensuring they are above a certain size. It has prompted further research, and informed councils and charitable groups on how to best support endangered braided river birds, like our wee friend the Wrybill. I’m sure there shall be some grateful kayakers out there too! I shall sign off this blog with an image of the Wrybill making the most of his unique laterally curved beak.

This article was prepared by Master of Environmental Policy and Management student Katherine Manning as part of the ECOL608 Research Methods in Ecology course.

Wrybill/Ngutuparore (Shellie, 2016, CC BY-NC-ND 2.0, via Flickr)

Here is a full citation for the article:

Duncan, M.J., Hughey, K.F.D., Cochrane, C.H., Bind, J. (2008) River modelling to better manage mammalian predator access to islands in braided rivers. Exeter, UK: British Hydrological Society 10th National Hydrology Symposium: Sustainable Hydrology for the 21st Century, 15-17 Sep 2008. 487-492

November 1, 2023
Kea pine for a new home?

Kea, our smart alpine parrots, are sometimes a little too clever for their own good. They are a species struggling to maintain large and healthy populations. Part of their problem is that they are very curious and seem to be fascinated by what humans do, and more importantly, often live in human-influenced habitat. This is not such a good trait when it leads them to interact with hazards like lead or toxins, nor is it useful if they find human ‘junk’ food.

This curiosity is also not helpful when we want to study kea. Many of the approaches that work with other bird species just fail for kea. Instead of going about their business they come and see what you are doing, and that’s not great for understanding key aspects of their life histories.

Spot the kea at the top of the tree! Image by Adrian Paterson.

I has some first-hand experience with researching kea about twenty five years ago, when I was a newly minted Lincoln University lecturer. I was helping Kerry-Jayne Wilson to supervise a masters student, Mark Jarratt. Mark was interested in how much lead, and other nasty waste, the kea were finding in the local Arthur’s Pass area, and consuming, in their habitat. For example, lead was present in paints, shotgun pellets and rubbish in the tips and kea were often observed eating it.

Mark had to catch kea to take blood samples to check for lead contamination. Catching kea can be fairly challenging. They are not easily fooled and they can learn by observing others. Adding to the difficulty was that we had to keep the birds in captivity for an hour or so as part of the procedure. And this was a problem.

We initially used a cage. We would capture a kea, put it in a holding cage, and then go and try and capture the next one. However, each kea would often figure out how to escape the cage. We would return to find a cage open and our patient free (and not likely to be so easily caught again). So then we took the cage with a kea into a small hut nearby, thinking that if the bird got out of the cage then they would at least be in the hut. Unfortunately, some of the kea managed to figure out how to open the windows in the hut. Moral: don’t work with animals smarter than you are!

So, when PhD student Jodanne Aitken came to James Ross and me and wanted to do a project on kea, I was a little hesitant. However, Jodanne is nothing if not persistent, passionate and persuasive, and a project on kea was begun.

Early morning in the plantation. The native forest in the distance was often commuted to and from by kea. Image by Adrian Paterson.

Jodanne was interested in how kea move about and utilise the landscape. Much of her PhD work is in the Southern Alps around Arthur’s Pass, where she is using transmitters to figure out just how mobile kea can be. Is that kea you see gnawing your car wiper blades from the local valley or could it be from several mountain ranges away? More on that in future EcoLincNZ articles!

Jodanne’s initial work was in looking at how kea might be using plantations of introduced pine and Douglas fir in the Nelson region. Forestry has become a dominant part of many regional landscapes, often hilly and where native forests once grew (and kea once flew). This is especially the case in the Nelson region. The question that Jodanne wanted to answer was whether these forestry plantations, typically monocultures with a lot of human activity, provide a net gain or loss for kea.

Jodanne filming kea foraging behaviour. Image by Adrian Paterson.

Are plantations the equivalent of barren wastes for kea, where there is little food and high densities of mammalian predators (not to mention hazards that humans introduce into an area)? Alternatively, do plantations offer new food resources and places to roost and nest? Of course there could be a range of outcomes from positive to negative.

Jodanne was able to work in forestry blocks run by Nelson Forestry Limited. Local workers were key to providing Jodanne with almost real-time information on kea presence within blocks that were being actively harvested. One advantage of working in plantations were the forestry roads that gave rapid, if a little hair-raising, access to most of these areas.

Jodanne was able to capture three kea and mount GPS trackers in fancy backpacks to collect movement data. She also observed kea during the morning and late afternoon-early evening periods for several months, mostly to record their feeding. Jodanne used direct and video observations to observe their foraging. Kea poo was also collected when available to get some physical information about diet.

The kea with transmitters spread their time between the plantation areas and neighbouring native forest. The majority of time was spent in the pines where they foraged, roosted and nested. Kea were observed eating pine seed, as well as tissue stripped off newly harvested Douglas fir logs. The faecal samples, well the bits that could be identified, contained lots of invertebrates.

Kea have discovered that they can strip the bark of newly harvested logs, scrape off the cambion tissue, chew this and get something nice out of it. (Maybe a bit like eating sweets?) This may be one of the attractions of being in plantations. Image by Adrian Paterson.

In short, as summarised in a NZ Journal of Zoology paper, kea seemed to be using the pine plantations in similar ways to more natural areas. Good news! However, one of three kea that carried a GPS recorder was killed by a cat. So, there may be some significant risks for kea spending a lot of their time in these areas. ‘Swings and roundabouts’ as they say.

Despite this being a relatively small scale study, it does indicate that we could learn a lot more about kea in these highly modified landscapes. Jodanne has taken this training and shifted her sights to a much larger scale project on kea movement in the Southern Alps and southern Westland.

Kea are one of the smartest bird species on the planet but they still need our help to let them survive the arrival of the smartest mammal species and the changes that we have made. Understanding this clever species is fundamental to helping them. This tricky challenge has been accepted by Jodanne and her research colleagues.

Article by Adrian Paterson, an Associate Professor in the Department of Pest-management and Conservation at Lincoln University.

September 14, 2023
The hotspots are where it’s at if you want to spot a cat: the search for the common leopard
The Himalayas are an almost mythical place, where mountains loom and the clouds surf down their sides before sliding into the forests below. The songs of rhesus monkeys, palm civets, and the occasional jackal sing out from the thick trees. This landscape is beautiful yet rugged. Travelling through is difficult for our human capabilities, in many cases impossible.

Now imagine. This is the backdrop you must navigate to discover the number of big cats that live there. To top it all off, your target is the shyest and one of the rarest of them all, the inappropriately named common leopard.

A common leopard relaxing in the sun
(Source: Daily Pakistan: Pakistan’s common leopard endangered due to loss of habitat)

Now, it’s not unusual that scientists doing field research are thrown into difficult situations. You might end up with dangers like Carlos Jared who innocently picked up a frog while doing fieldwork in Brazil, discovering frogs can be venomous. Or you might accidentally glue yourself to a crocodile while attaching a radio transmitter like Agata Staniewicz did (find that and more hilarious field research fails here).

But when you’ve got a shy animal, add in an impassable landscape, plus the addition of the very real and dangerous threat of bumping into rebels which is, unfortunately, the reality in parts of Pakistan, you’ve really got your work cut out for you.

This momentous task is one Muhammad Asad, PhD student at Lincoln University, took on as he bravely set off to northern Pakistan. Nobody had done this before and the leopard landscape was mostly unknown. But he was up for the challenge.

The not-so-common leopard

Leopards are found all over the world, the most widespread of all land-based carnivores. They’re incredibly adaptable, able to make their homes in all sorts of climates: from the savannas of Africa, the tropical forests of South East Asia, to the freezing mountains of far north Russia. They even make it work when humans move in.

Their only request, being rather introverted, is that they have lots of space. They’re very territorial, protecting their home range fiercely. But honestly, a bit of peace is a reasonable request!

Despite this incredible flexibility, common leopard populations are in decline. They’re no longer found in 63-75% of their historic range. The decline in Asia is even bigger, with an 83-87% drop! It’s no surprise that these gorgeous cats are listed as critically endangered.

The majestic common leopard
(Source: Daily Pakistan)

Leopards are facing many different threats. The main ones are:
- habitat is lost or changed,
- trees cut down,
- inbreeding from being cut off from one another,
- human developments being built near their protected ranges,
- prey disappearing,
- poaching,
- and human-wildlife conflict.
Clearly, these cats need protection. So, leaving New Zealand and heading back to his native Pakistan, Muhammad took the first step to build a conservation plan; he had to figure out how many leopards there were and where they were found.

To do this across the entire country would be too big a job. Instead, he focussed on the Gallies and Murree Forest Division in northern Pakistan, lying in the outer Himalayas. Here, leopards are protected under the law. Even so, there are often no checks for this, with hunters easily getting away with it. This is made worse by the slow and sometimes non-existent compensation programmes, programmes designed to reimburse farmers who have lost livestock to a leopard attack. The locals often resent the leopards. But it’s hard to blame them when people, including children, are occasionally attacked and killed.

Leopards are poached frequently in Pakistan. Cubs are trapped to sell in the illegal pet trade or body parts and skin are taken for sale. Skin, claws, and teeth are sold in north Pakistan.
(Source: Raj K Raj/Getty Images)

Estimating the number of leopards in an area is very tricky. They have large territories with very few cats within each area. Figuring out where to look, especially when the landscape has the worst access, is the key to success.

How to find leopards

Muhammad and his crew began with a questionnaire survey. They asked people from local communities who lived nearby to fill these out. They asked about losses of livestock, when the attack happened, and the type of injury, for example, bite marks on the neck, missing dogs, or human casualties.

Based on the information from the locals, they ended up with 63 different sites where they could focus the leopard hunting efforts. A much better start!

Next, they moved into these sites, peeling their eyes for signs of poop, territorial markings (such as peeing on a tree), and tree scratches. These signs meant one thing; here be leopards.

With this proof, they set up special cameras, known as camera traps, on either side of the trail, ready to capture the cats on the silver screen.

They also set up cameras on 5 connecting trails which hadn’t shown any signs of leopard action. These were used to see if they could capture leopards in areas where they had left no signs. As new leopard trails were discovered, the camera traps were moved to snap those too.

Sampling locations of the camera-traps survey in Gallies Forest (Ayubuia National Park, surrounding Reserved Forest and Guzara Forest), and Murree Forest (Protected, Reserved and Municipal Forest). Country map (top left – green). Study area showing different city boundaries (middle left).
(Source: From paper)

A leopard can’t change its spots – a handy identification tool

You may have heard the proverb that a leopard can’t change its spots. This is supposed to teach us that we all stay true to our nature, even if we pretend we’re different. But it turns out when it comes to leopards it’s 100% true! The coat of a leopard is as unique as our fingerprints. Incredibly useful when you’re a scientist trying to tell the difference between two cats in a grainy photo!

Their gorgeous spots are a bit like the shape of a rose, giving them the name ‘rosettes’. This means that by matching up the images of the rosettes you can figure out if it’s the same cat. The best place to match things up is on either side of their back legs or the top of their tail.

Example of an individual being identified using the rosettes on the tail
(Source: From paper)

This is trickier than it sounds. The rosettes change shape as the leopard moves. And it can look different depending on the angle it is to the camera. But still, it’s a pretty helpful method to avoid double-counting cats. Double counting would give you a very different population size! You can find out more information on leopard identification techniques here.

Example of when the spots don’t match up.
(Source: From paper)

So, how many are there?

In 2017 Muhammad estimated there were between 16-24 common leopards in the Gallies and Murree Forest Division. This went down to 7-12 in 2018.

However, they don’t think the population dropped. In 2018 they got fewer clear images making it harder for them to identify the cats. They think the real number could be closer to 12-18, meaning its range overlaps with the 2017 estimate.

But, this might not be the case. In 2018, Pakistan was suffering from a drought. Perhaps the leopards had been forced to move out of their territories to look for food. So far there hasn’t been any research on leopard movements in relation to strange weather. This would be an interesting thing for someone to look into (are there any leopard enthusiasts up for the task?).

Or perhaps this drop is real. Poaching and unreported killings are still huge in Pakistan. Plus, Muhammed and his team did find signs of hunting. So the reason could in fact be nefarious.

Regardless of the reason, Muhammad estimated there to be 8-12 leopards and 3.5-6.5 leopards per 100 km2 in the Gallies and Murree Forest Division. They also confirmed they lived in the Swat, Dir, and Margalla Hills, even though locals as well as wildlife departments thought they had disappeared.

These estimates are not 100% accurate. But the team is pretty confident that they are close to the true number. All in all, a great success.

Mother common leopard and her cub.
(Source: Daily Pakistan)

What next?

Now there’s a basic understanding of how many leopards there are and where they like to hang out, we can start to protect them.

With this information, we can:
- Use the leopard hotspots to keep an eye on the population trends and demographic changes over time.
- Decide on the most important conservation areas. Special attention should be given to the corridors that join areas together to protect the long-term health of the leopard populations.
For example, Muhammad discovered that 70% of leopards killed for revenge in the Guzara Forest happened outside of the Reserve area, close to the village, and in winter. That tells us we should focus the conservation efforts on the hotspots in the Guzara Forest surrounding the Reserved Forest so that human-leopard conflicts can be reduced.

There’s still a lot of work ahead for the common leopard in Pakistan. But with Muhammad on the case, their future is looking a little brighter.

You can read Muhammad’s research in full here: The Un-Common Leopard: presence, distribution and abundance in Gallies and Murree Forest Division, Northern Pakistan

This article was prepared by Master of International Nature Conservation student Kat Douglas as part of the ECOL608 Research Methods in Ecology course.

Full citation: Asad M, Waseem M, Ross JG, Paterson AM (2019). The Un-Common Leopard: presence, distribution and abundance in Gallies and Murree Forest Division, Northern Pakistan. Nature Conservation 37. 53-80. https://doi.org/10.3897/natureconservation.37.32748
August 11, 2023
Fishing for possum DNA

When I was a child, I was fixated on animals. In fact, 5-year-old me would go around telling all the primary school mums that I wanted to be a Palaeontologist. This was often met with some strange looks, quite possibly because they didn’t even know what a Palaeontologist was themselves. Since then, I have been less focused on digging up dead animals and more interested in protecting the ones that are still alive.

In New Zealand, tourism and agriculture are arguably the biggest money-maker industries. People flood from overseas to check out the clean green image being advertised in their home countries for themselves. The ‘Great Walks’ lead tourists through the rugged bush that New Zealand has to offer. Along the way they might even see some of our diverse flora and fauna, of which most can not be found elsewhere on Earth.

On the other hand, the dairy, sheep and beef industries in New Zealand, earn large amounts of overseas revenue. This all started when Samuel Marsden introduced shorthorn dairy cattle to New Zealand from New South Wales and the rest is history.

https://www.australiangeographic.com.au/topics/wildlife/2017/04/killer-possums/

This brings me to the devious, but very cute looking, Brushtail Possum, Trichosurus vulpecula. In Australia, the Brushtail Possum is a protected species. In New Zealand they are a serious threat to our homegrown species. Possums compete with our native bird species for food and inhabit the same areas. These fluff balls are omnivores. In addition to eating the leaves off trees, they rob the nests of birds and eat the chicks and eggs.

Bovine tuberculosis is a disease that affects many farm animal species. Possums are the biggest carriers of tuberculosis and can infect herds of dairy cows, causing serious illness to the animals and a large vet bill for the farmer. Due to these factors, New Zealand tries incredibly hard to get rid of these furry mammals. One important thing that we need to know is where these possums are present and and in what numbers. For a nocturnal and relatively cryptid species, this is a lot harder to do than simply call a roll!

The use of trace DNA to monitor animals, such as possums, is a relatively new concept. However, a trial was held in Canterbury where researchers collected DNA from saliva left on WaxTags and Chewcards to determine the number of possums in an area and check whether these individuals were Tuberculosis carriers. From the initial field study, it was found that multiple possums would bite the WaxTag and Chew cards which made it difficult for the lab team to isolate certain animals. A new device to collect data was needed.

A mechanical collection device was created which would remove the bait after one animal had bitten into it, which protected the saliva and therefore the individual DNA could be distinguished. The device was a bit like a fishing line, catching its prey and then reeling in the DNA! Researchers found that the mechanical device allowed the DNA to be collected and more easily sequenced. They also found that the genetic material was more easily recovered from covered WaxTags than on the uncovered WaxTags.

Mechanical device created to protect DNA sample on the WaxTag.
Image from: A New Non-Invasive Method for Collecting DNA From Small Mammals in the Field, and Its Application in Simultaneous Vector and Disease Monitoring in Brushtail Possums

Cameras used in the field trials picked up that the possums interacted with the new WaxTags, and 87% of the devices were triggered after the first interaction. This is a positive point because in order for a monitoring device to be useful, the target has to interact with it.

This new way of collecting trace DNA samples was a success. DNA from Brushtail Possums was able to be amplified for genetic identification and was able to detect if diseases were present. The combination of the device being interesting enough for the targets to interact with, and the subsequent DNA extracted being protected until collection, means that it is ever more likely that technology like this can be used for other pest species to determine their disease risk.

The current study is the first to collect trace amounts of possum DNA and keep it protected from the elements until genetic analysis has taken place. This is a pretty big step for DNA collection methods. However, transmission of infectious diseases by vectors, such as possums, is density dependant. More collection devices need to be installed in these areas being studied to create ‘encounter’ history for individuals to determine population density and to calculate the likeliness for for transmission of these vector carried diseases.

This research suggests that there are new ways for non-invasive monitoring pest populations. The road to New Zealand being predator free by 2050 is a long one, but is shortened by the impressive new technologies being developed in the pest management space. This technology is key for determining the populations of pests in their area and how likely their livestock are to contracting devastating diseases such as Bovine Tuberculosis.

Dealing with pests may not be the most fun thing to do week to week, however, determining where populations are and where the risks lie can help experienced personal to more effectively manage pest populations and get New Zealand back to where we should be, mammal predator free.

This article was prepared by postgraduate student Rebecca Anderson as part of the ECOL608 Research Methods in Ecology course.

Emami-Khoyi A, Agnew TW, Adair MG, Murphy EC, Benmazouz I, Monsanto DM, Parbhu SP, Main DC, Le Roux R, Golla TR, Schnelle C, Alizadeh H, Csányi S, Heltai M, Jansen van Vuuren B, Paterson AM, Teske PR and Ross JG (2021) A New Non-invasive Method for Collecting DNA From Small Mammals in the Field, and Its Application in Simultaneous Vector and Disease Monitoring in Brushtail Possums. Front. Environ. Sci. 9:701033. https://doi.org/10.3389/fenvs.2021.701033

September 19, 2022
The spitfire: a sure-fire way to eradicate stoats?

Stoat! Look out, the RAF (Really Awesome Field-research) is coming! Photo CC BY-NC 2.0 Stuart Smith, Flickr

Stoats, weasels and ferrets: the terrifying trio. If New Zealand’s native birds could speak, I’m sure that’s how they would refer to them as they swap stories of escape and near misses. Widespread, wily and lethal, the stoat is considered the greatest threat to the survival of many endangered and threatened native birds on the mainland, such as the takahe, orange-fronted parakeet, and Leonardo DiCaprio’s favourite, the kakī (black stilt).

Here are the cold, hard facts. Humans introduced stoats from Europe to control rabbits in the 1880’s, against the advice of ecologists at the time. They have since run rampant over our native bird species, throwing many populations into a drastic decline. Like clever little kleptomaniacs, they sleep on beds of feathers stolen from our most treasured and rare birds.

We must eradicate stoats from areas of New Zealand if we are to have an extant bird as our national icon. The prevailing question is, how?

Photo CC BY-NC-ND 2.0 Shellie Evans, Flickr

Never fear, the Spitfire is here! Unless you are a stoat then, yes, be afraid. The Spitfire is a re-setting toxin delivery device which was trialled in the Blue Mountains of Otago in 2013. 65 Spitfire devices were set up for approximately six weeks. Each device was capable of delivering 100 lethal doses of the stoat killing toxin PAPP (para-aminopropiophenone).

The stoat population was monitored in the area during this time using trail cameras and tracking tunnels in order to measure the Spitfire’s effects.

The project was carried out by Elaine Murphy, Tim Sjoberg and James Ross from Lincoln University, along with researchers from Wildlands, the Department of Conservation and Connovation. They found that the Spitfire knocked down 62% of the stoat population in the trial area.

The Spitfire is a very picky individual, only delivering the lethal dose of poison to a suitor of the right body size and shape. The device is able to do this due to its dual sensors. Cameras trained on the Spitfire devices during the trial in Otago recorded no instances of non-target species, such as rifleman, receiving any of the poison. PAPP has been registered for use in stoat control since 2011, but is mostly available for use in fresh meat lures, which are labour intensive to produce and expire quickly.

The 2013 trial was a success for the Spitfire and PAPP, but it was not without it’s issues. It was a trial after all! Many of the devices malfunctioned before the end of the six week trial due to design faults in weather proofing and circuitry. The conclusion was that the Spitfire showed promise, but lacked in stamina and sturdiness.

Kereru in Kawakawa, Photo CC BY 2.0 Geoff McKay, Flickr

All was not lost! In 2016 the New Zealand Government announced its goal to become predator (rats, mustelids and possums) free by 2050, which led to a funding initiative called ‘Products to Purchase‘ from PF2050 Ltd. Five products were selected, based on their expected contribution to the cause, to receive funding to fast track their development to a marketable level.

In 2019, the first five successful applicants were named, and who should be among them but our voracious Spitfire. A Tauranga based start-up called Envico Technologies Ltd (ECT) went back to the drawing board with the device. They re-engineered and re-invigorated the design and produced a prototype they could now commercialise, all with the help of the funding from PF2050 Ltd.

The Spitfire was back in the game, with the new design finalised in 2020. The latest model promises a longer lifespan of one year, during which no maintenance or refills are required. It’s widely known that the main cost in stoat control is in the field hours with bait station and trap operations, so this hands-free option is looking like an economical as well as an effective choice.

Also on the toolbelt of the new Spitfire model is a bluetooth data logger, which records the date and time of trigger events. ECT envisions this feature being highly beneficial for monitoring pest populations and assisting with re-invasion events in eradicated areas. Because of it’s long field life, the Spitfire becomes an attractive option for use in more remote areas where previously the only viable option has been aerial 1080 drops. If you have a ‘Ban 1080’ bumper sticker, this product may be for you.

Brushtail possum and her joey at Tārerekautuku Yarrs Lagoon, Photo Katherine Turton.

Just when you think it can’t get any better, a distinct advantage of the Spitfire is that there are few issues with alternative food sources or bait shyness. Stoats don’t have to bite, pull, stand on a treadle, or count backwards from 100 to receive a lethal dose. They are simply drawn in by an automatic lure dispenser that keeps a delicious mayonnaise paste coming all year-round.

The Spitfire is an intellectual. It has smart capacitive sensors that can detect and measure anything that is conductive. It can tell the difference between the long sausage body of a stoat and a little compact rifleman, preventing our inquisitive native species from receiving the toxin. When the Spitfire senses a stoat it launches a lethal splurge of toxin onto the abdomen, after which the animals are instinctually driven to groom off the mess.

ECT joined forces with the Department of Conservation and Boffa Miskell to conduct field trials from 2020-2022. Alongside the stoat design, a model specifically for our Australian foes, the brushtail possum, was also trialled using a Diphacinone and Cholicalciferol toxin instead of PAPP.

Field trials are about to conclude for the Spitfire and ECT are expecting to roll out the finished product at $200 a piece. There is also talk that a rat specific Spitfire is now in the works! This innovative technology is paving the way for more effective pest control not just here in New Zealand but worldwide. Conservation groups get your wallets ready and watch this space!

For more information, see the article on the Sptifire trial in Otago and follow ECT to keep up with their latest technological solutions for conservation!

This article was prepared by postgraduate student Katherine Turton as part of the ECOL 608 Research Methods in Ecology course in her Master of Pest Management degree.

August 1, 2022
Seduced by the Stoat Stench

As a child who was raised next to the ocean, I suppose it’s only fitting that the beach is my attractant. Something about the sand between my toes takes me back to when I was 6. My talents were at a peak as I managed to take the win in multiple sandcastle competitions. The sea gives me a sense of security and allows my mind to reset, clearing all worrying thoughts. And of course, it is the foundation behind most of my hobbies; fishing, diving, swimming (and sandcastle building). The beach has always been a part of my upbringing, a place where I enjoy the company of family and friends.

Beach Day – CC BY-NC-ND Image by Anna Meban

One of the things I found most interesting after a trip down to the beach was how my little jack russell paid far more interest in me when I returned home. Now maybe this had something to do with us neglecting to take him with us, but he would always sidle up to me, frantically sniffing and then stare at me longingly, as though I had betrayed him. He knew I’d made friends with a passing puppy on the beach and he knew that whoever had left these hairs entwined in my clothing was not him.

It’s important to remember that these attractants differ, especially when they include scents such as urine, scats and bedding odours. Yes, you read that right, these are the types of odours that Lincoln University’s Elaine Murphy and James Ross, along with their fellow colleagues, investigated in terms of the power of attraction in stoats (Mustela erminea). More specifically their study discussed whether body odours of reproductively fertile (oestrous) stoats have the potential to be used as lures for pest trapping.

Their study, published in the journal Animals, tested these lures in a series of lab and field trials. Lab trials were undertaken at Lincoln University and involved wild-caught stoats. The experiment was set out in a way where each odour sample was placed in a metal mesh tea ball, allowing stoats to smell but not interact. As well as this, a control sample was used, consisting of unscented Dacron, allowing stoats to choose between scented and unscented chambers.

The field trials differed slightly, with the lure stations providing a menu selection of stoat odours and more traditional lures consisting of hens eggs and dried rabbit meat. The field trials took place in a range of New Zealand’s well-known locations, Abel Tasman, Lake Rotoiti (Tasman) and the Coromandel.

Exploratory Stoat – CC BY 2.0 Charlie Marshall (Flickr)

This got me thinking about how important scents are as an attraction method for animals, even for humans themselves. It may be the scent of home-cooked meals in the kitchen. The strong scent of cologne as your crush walks by. The smell of salty air drawing me to the ocean and reminding me of home. Everyone has something they are attracted to but these things differ depending on the person… or species.

In Abel Tasman and Lake Rotoiti, the trials compared fertile female stoat bedding odours to a dried rabbit meat block formulation. In the Lake Rotoiti trials, they also tested a combination of both lures together. It was the Coromandel trial that grabbed my attention, as this focused on whether male odours had the same charm as females. The trial was divided into two stages, first the male stoat bedding odour was partnered with either dried rabbit or hen eggs, and second, the male bedding odour was trialled on its own.

The lab and field trials both showed very promising outcomes for the control of stoats. In the captive animal trials, stoats had greater interaction times with stoat odours than with the control dacron. Stoat odours were just as much preferred by stoats as the hen eggs and dried rabbit meat. Male odours were also equally effective attractants for both males and females showing interest in the scent of the opposite sex.

So what can we do with these alluring aromas?

Well, it is becoming increasingly more evident that food lures in the wild are not always the most effective way of targeting stoats when using kill traps and bait stations. Although these are the best techniques at the moment, conservation workers still struggle to catch stoats in many locations. Elaine and her colleagues mention how this is likely due to every individual having different preferences (basically a personality), as well as stoats being spoilt for choice in terms of food sources in certain areas.

With all pest control there will be some animals that manage to dodge the bullet. The use of odour as a lure adds another technique into the mix. This new tool may be just what we need to increase chances of stoat capture rates in areas where food is abundant.

Stinky Stoat – CC BY-SA 2.0 Airwolfhound (Flickr)

What’s even better is that, as stoat populations begin to decline, this scent lures method will only become more effective! As desperation sets in and survivors scramble to find mating opportunities, they will lead themselves right into their own funky smelling fate.

But wait, there’s more…

From the results gathered within this study, it is thought that these stinky stoat odours may have even more potential than just capturing stoats. In conjunction with traditional lures, these odours also captured the attention of ferrets and rats. With the looming deadline of ‘Predator free 2050‘, this research could be the next step in trying to reduce these sneaky (and stinky!) pests.

More research is now needed to figure out which chemicals are driving the attraction and how to produce these lures in a form that can be utilised nationwide, Elaine, James and their colleagues are on the trail of a breakthrough scent that has the potential to revolutionise predator trapping methods. Something to think about next time I’m at the beach.

The author Anna Meban is a postgraduate student in the Master of Science – Conservation and Ecology taught at Lincoln University. This article was written for an assessment for ECOL 608 Research Methods in Ecology.

April 18, 2022