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Annual Report 2015â€“16

Above: View from saddle of Queen Charlotte Track, Bottle Rock peninsula Designed by Rory Harnden (Ink Digital) Photos by Rory Harnden (Ink Digital), Alan Cressler (DOC), Robyn Janes (Media Fix), Briar Cook, Michael Tunnicliff, Ripley Dean, Al Bramley, Tom Agnew, Tim Sjoberg, and Nick Mulgan (ZIP)

ZIP Annual Report 2015-16 Forewords ��2 Devon McLean, Board Chair Al Bramley, CEO

Remove and Protect ��7 ZIP Team and locations �� 11 Wellington office, Karori Predator behaviour facility, Lincoln University Bottle Rock peninsula field development site

ZIP Board ��12 Sharing our learning �� 13 Removal of rats and possums �� 15 Initial Removal at Bottle Rock Removal at next scale

‘Virtual barrier’ ��16 Conditions at Bottle Rock peninsula during 2015/16 ZIP’s ‘virtual barrier’: a systems approach to predator control Barrier layout Virtual barrier for rats – performance and leakage Virtual barrier for possums – performance and leakage A note on stoats

Barrier learning and enhancement �� 22 Rats Possums Blending the barrier with predator fencing

Detection and response ��36 Radio-collared invading rats Detecting ‘Gen One’ – a new strategy Rat reinvasion event (Feb-June 2016) Automated detection Detecting and removing ‘lonely’ roaming possums

Stoats ��47 First iteration of the stoat virtual barrier and stoat detection Stoat ‘social’ lures Using cameras to detect stoats A giant pitfall trap for stoats

Future direction: Scaling up ��54 Financial summary ��56 Founding partners Investors Financial summary and Auditors’ report

this page: Susannah Aitken baits a TUN200 trap at Bottle Rock peninsula

Forewords

Devon McLean Board Chair

This report comes at a time of remarkable new momentum for the vision that predator control could have a transformative impact not only on our beleaguered biodiversity but also our economic and social prospects as a nation. ZIP is playing its own part in supporting that momentum by allowing us all to contemplate new and innovative ways to approach landscape scale predator control. The commitment in the last year by the NEXT Foundation to join with others to initiate new projects including Taranaki Mounga and Predator-Free Wellington combined with the Governmentâ€™s stunning announcement of PFNZ 2050 are further evidence of this changing momentum. 2

While pursuing a focused vision of eradicating rats, possums and stoats from landscapes AND defending them from reinvasion, ZIP is also demonstrating a novel way to organise research and development by combining scientific, engineering, economic and modelling skills in an agile framework. This multidisciplinary, rapid test and prototyping approach with a constant eye to cost effectiveness is yielding remarkable results

and the team are on track to develop systems that will become an essential part of the delivery suite for PFNZ 2050 over the next few years. I would like to thank our partners Department of Conservation, NEXT Foundation, Morgan Foundation, Jasmine Social Investments and the dairy industry consortium of Fonterra, Tatua, Synlait, Westland Milk Products, Open Country and Miraka for enthusiastically backing the approach taken by ZIP and actively engaging in the project to enhance the effort.

Our directors have given willingly of their time and expertise and also engaged closely with the development team. Al Bramleyâ€™s exemplary leadership of that team both technically and through developing a culture that allows the innovative approach to flourish, is greatly appreciated by all. Above: KĹ?whai in bloom at Resolution Bay

Al Bramley CEO

Innovation at ZIP often begins with a surprising observation from the field, or through exhaustive (and often exhausting!) re-examination of the data, generating new questions or ideas. Literature reviews, urgent experiments, and rapid prototypes of tools and techniques quickly follow. Promising tools or techniques then move to observational testing or tentative field trials, invariably leading to rapid evolution as we improve our understanding of the challenge. This approach has allowed the ZIP Team to amplify those developments that show promise or modify (even terminate) those that fail to perform as anticipated. The team at ZIP believe you haven’t innovated anything until you have enabled a change in practice. That’s why one of the highlights this year has been working with the Department of Conservation, Regional Councils, and the Ministry for Primary 4

Industries to enable remote monitoring for live capture traps, opening the way for a 95% reduction in the labour required. This change helps ZIP to unlock an economically viable ‘barrier’ and detection/ response for possums – a reliable leg hold trap system that we have now tested for over 250,000 trap nights! Our developments continue to grow at our field site, Bottle Rock peninsula. We are now able to intercept over 60% of possums attempting to breach the first defence line in the virtual ‘barrier’. We have learnt that, for ship rats, peanut butter, Nutella, and cheese are the best performing lures

to date; and, with the addition of male ship rat bedding (our first ‘social’ lure), a further increase in attractiveness looks likely. But we were surprised when our released ‘invading’ rats and stoats didn’t act quite as we expected, leading to a radical rethink of our detection strategy! All our work at Bottle Rock is made possible only by the support of the local community, the Sounds DOC team, and Te Ātiawa and Rangitāne Iwi. More recently, we have begun to think about creating barriers to prevent reinvasion in a rural or urban context. To this end, we have been experimenting with lowering the height of predator fences to only exclude rats, possums and stoats. Work to date indicates that an 800 mm high predator fence may be all that is required for stoats, with rat and possum jumping heights yet to be tested. We have also demonstrated that bright light can be used to ‘steer’ ship rats into traps. All this learning has been accelerated with the opening of our 2ha predator enclosure, thanks to investment from our Dairy Industry partners. As we cement our learning and techniques, we have begun some significant engineering projects to reduce the capital cost and increase the efficiency of the ‘Remove and Protect’ system. We are working with Motovated, SCION, and Talbot Engineering to produce a wood fibre-plastic composite leg hold trap platform, and with Infact Design to develop an automated food lure dispenser.

I believe a rat and possum barrier is looking more feasible than ever. As we look forward, with scaling up our operations to a peninsula of approximately 4,000 ha in mind, we will focus more intently on the rat-related challenges of initial removal and incursion detection and response. Given their mobility, stoats will remain largely ‘on hold’ until we move to that next scale, but we have already seen promise with oestrous stoat lures and camera-based detection. 2015/16 saw ZIP become more outward facing, as we began to share our learning through our website. The year also saw us deliver on average one presentation per week. Casting our minds forward to the next scale site, we need to find a community who is committed to restoring their native biodiversity. As you will read, the high performing ZIP team have lifted the pace of learning and development on the Remove and Protect model. The team capacity has doubled and our in-house expertise increased, particularly in predator behaviour, statistical analysis, and field testing. Vitally, we have kept each other safe, and had a lot of fun together along the way as we keep pace with our ever evolving work. I would like to extend my sincere thanks to the ZIP Team and our partners for a productive and enjoyable year, and I am delighted to present the 2015/16 ZIP Annual Report.

above: A calm evening at Resolution Bay 6

Remove and Protect Zero Invasive Predators Ltd (ZIP) was established in February 2015 as a research and development charitable entity, with the mandate to develop operationally ready, innovative, strongly supported technologies to enable the complete removal of rats, possums and stoats from large mainland areas, and protect these areas against reinvasion. We call this model Remove and Protect.

The Remove and Protect model involves three key streams of work:

1. Initial removal of target predators from an area 2. Holding a line of defence across the land to protect an area against reinvasion by predators 3. Detecting and removing invaders before they significantly impact on a protected area Remove and Protect is well suited to peninsulas as they are relatively easy to defend, with only one major exposed front. This means that interception efforts can be concentrated within a relatively small zone to protect a much larger area.

ZIP is currently trialling Remove and Protect at Bottle Rock peninsula in Queen Charlotte Sound, where an approximately 500 metre wide ‘virtual barrier’ spanning the 2km neck of the peninsula protects an area of approximately 400 hectares. The Remove and Protect approach, if successful, will bring New Zealand closer to achieving predator-free status by making it possible to: • completely remove rats, possums and stoats from large peninsulas, at a scale where it is neither desirable nor possible to construct predator fences

• reduce our dependence on the repeated wide scale application of toxins at chosen sites • enable communities to restore native biodiversity and create an environment on the mainland where (in time) ecological integrity could rival that of predator-free offshore islands • eliminate the economic impact of these predators

Bottle Rock + Queen Charlotte Track QUEEN CHARLOTTE TRACK

Ship Cove/Meretoto

Virtual Barrıer

Protected Area Bottle Rock Peninsula

Resolution Bay 1km

Above: A section of the defence zone or â€˜virtual barrierâ€™ protecting Bottle Rock peninsula from reinvasion by rats, stoats and possums.

Al Bramley

Chief Executive Officer

Susannah Aitken Executive Assistant

Phil Bell

Business Manager

Helen Nathan Predator Ecologist

Duncan Kay Field Team Lead

Pete Morresey Field Ranger

John Wilks

Principal Engineer

Briar Cook Field Ranger

Nick Mulgan

Modeller and Geospatial Analyst

Michael Tunnicliff Field Ranger

Elaine Murphy Principal Scientist

Tim Sjoberg

Animal Behaviour Technician

James Russell Science Advisor

Tom Agnew

Animal Behaviour Technician

ZIP Team and locations Wellington office, Karori ZIP’s office is located in Wellington, where many of our collaborators in the public and private sectors are also based. The office is located on Waiapu Road, Karori, adjacent to Zealandia Sanctuary. Key activities carried out in the Wellington office include: • Developing ZIP’s strategy and evolving our work plan

• Analysing data gathered at our field development site, modelling and forecasting future performance • Designing trials to test new tools and techniques • Working alongside partners to enable rapid uptake of our model and ensure our approach is integrated into the Predator Free 2050 vision

Predator behaviour facility, Lincoln University ZIP has three team members based at our predator behaviour research facility in Lincoln. Key activities carried out by our Lincoln-based team include: • Initial research and proof of concept trials on lures, tools and techniques before large scale testing at ZIP’s field site

• Providing advice on predator behaviour to maximise our ability to intercept or detect target species • Working alongside Christchurch-based R&D contractors and engineers to develop novel solutions for predator control

Bottle Rock peninsula field development site ZIP is currently trialling the Remove and Protect model at Bottle Rock peninsula in Queen Charlotte Sound, where tools and techniques (both existing and novel) are able to be trialled in a ‘real world’ setting. A ‘virtual barrier’ made up of a number of ‘defence lines’ spans the 2 km neck of the peninsula, protecting an area of approximately 400 hectares from reinvasion by rats, stoats and possums.

Each defence line is made up of a variety of control tools, intensively spaced to guarantee encounter by target species. Within the protected area, prototype detection tools are being trialled to enable early detection and timely response, in the event of an incursion. Information gathered by the ZIP field team then informs further development and refinement of the system and tools. 11

L-R: Charles Daugherty, Devon McLean, David Flacks, Al Bramley

ZIP Board The ZIP Board has met three times during 2015/16, and remains grounded in the teamâ€™s work with visits to the field development site and Lincoln facility.

Devon McLean

David Flacks

Charles Daugherty

Michael Slater

Board Chair

Board Director

DOC Senior Liaison Michael Slater is not a Board Director but represents the Department as a partner at Board meetings.

Board Director

DOC Senior Liaison

Sharing our learning ZIP has deliberately kept a low profile since our establishment in February 2015 for two reasons: â€˘ We were tasked with an ambitious technical challenge, which has been our primary focus to date; â€˘ We are still gathering the data (and scientific rigour) to support our observations from the field; and therefore are still gathering proof before we influence new practice. However, as our work has progressed and others within the conservation sector and communities of interest have become aware of us, we have worked to develop our communications to ensure our work is well understood, to enable

innovators and potential collaborators to contact us and share their own learning, and in time to provide insights from our field sites for others who are carrying out predator control. The main vehicle for this has been the development of our website â€“ www.zip.org.nz. Here, we are sharing our story, and detailing some of the findings from our trials at Lincoln and Bottle Rock peninsula. Members of the ZIP team have also attended a number of public and industry events during 2015/16, delivering an average of one presentation per week over the course of the year. 13

Rat kills January 2015

Possum kills January 2015

Rat kills March 2015

Possum kills March 2015

zero rats September 2015

zero possums June 2015

Removal of rats and possums Initial Removal at Bottle Rock After establishing the virtual barrier in November 2014, the removal of the approximately 5,000 rats and 3,000 possums at Bottle Rock was carried out using a combination of non-toxic aerial prefeed followed by hand laid 1080, and

then ground based bait stations and trapping on a 100 x 60 metre grid. It took approximately 6 months to remove all possums and 12 months to remove all rats. The total cost of this eradication was estimated at $550 per ha.

Removal at next scale Our initial work at Bottle Rock clearly identified removal, especially of rats, as a significant challenge, and the methods used at Bottle Rock are not believed to be feasible at a larger scale site given the high cost per hectare and long timeframes involved. Starting in 2016/2017 we will be undertaking two projects targeting initial removal: 1. The â€˜1080 to Zeroâ€™ project will see us working alongside the Department of Conservation, with advice from experts in the Island Eradication Advisory Group, Landcare Research, and OSPRI, to develop a prescription for aerial 1080 that completely removes all individual rats and possums. This work is timed for August to December 2016 in Taranaki, and will be carried out within the Taranaki Mounga operational area, as part of the DOC Battle for our Birds 2016 programme. 2. We are also working alongside the Department of Conservation to assess the feasibility and risk of enabling alternative toxins for use in mainland removal operations behind a virtual barrier and/or predator fence.

Taranaki Mounga

He Kawa Ora Back to Life The Taranaki Mounga project is an ambitious conservation partnership between NEXT Foundation, Department of Conservation and Taranaki iwi to make Egmont National Park the first predator-free national park, creating a haven for native wildlife. taranakimounga.nz

â€˜Virtual barrierâ€™ Conditions at Bottle Rock peninsula during 2015/16 ZIP began its work at Bottle Rock peninsula during the 2014 beech mast event, resulting in significant rat pressure in the early months. In autumn 2016, the area adjacent to Bottle Rock peninsula experienced low to moderate beech mast conditions, with a mild autumn followed by a late winter. By mid-2016 there was a

high level of food in the Queen Charlotte area, resulting in high populations of both rats and possums and increasing pressure on the virtual barrier. We have also been surprised to discover that the plentiful food supply on Bottle Rock enabled rats to continue breeding throughout autumn and winter 2016.

Pressure from rats and possums Possum Pressure

<< Version 1 (Dec-14 thru Jan-16)

Above: Number of rats and possums caught at Bottle Rock each month. We believe the 'peak' in possum pressure during March and April 2016 may have been caused by the increased effectiveness of Defence Line 1 (D1) following the barrier reconfiguration drawing an increased number of possums into the system.

Rat Pressure

Version 2 (Feb-16 thru Aug-16) >>

ZIP’s ‘virtual barrier’: a systems approach to predator control The virtual barrier ZIP is developing proposes to screen 99% of rats, 95% of possums and 90% of stoats that attempt to enter a protected area. This presents a very different challenge from carrying out predator control in a suppression context, where control is ongoing throughout the landscape to keep populations of target species below a certain threshold. In a Remove and Protect system, all target individuals are initially removed from the protected area, therefore ongoing suppression is not required. However, a range of lures and devices is needed to account for a variety of behavioural drivers for animals encountering the system as

they attempt to invade. Therefore, the virtual barrier at Bottle Rock contains a number of different food lures, ‘social’ lures such as oestrous stoat bedding, and other novel lures, along with a range of tools with different architectures and placement. The efficiency gain in this approach is not made by finding one tool that is most effective and employing this at low density across the landscape, but by using a range of highly effective tools at high density in a small area to protect a much larger area from invasion.

Version 1 barrier performance rats and possums

Barrier layout The first version of the virtual barrier targeted rats and possums and consisted of 6 defence lines, 100 metres apart, comprising bait stations and traps placed every 10 metres along the lines. Over the first 12 months a number of rolling improvements were made and the barrier intercepted approximately 95% of rats and possums (or, in real numbers, approximately 2 rats and 1 possum â€˜leakedâ€™ through the 2 km long barrier every month). 18

In an attempt to improve the performance and efficiency of the barrier, it was reconfigured in January 2016, to include four lines for rats (again with toxins and traps); and three lines for possums (traps only).

Virtual barrier for rats performance and leakage Early indications suggest the reconfigured barrier is performing well for rats, with further improvements already identified for the next iteration in late 2016.

Version 2 barrier performance â€“ rats

Virtual barrier for possums performance and leakage Unfortunately, as at 30 June, the reconfigured possum barrier appears to be leaking more than the previous version. We now believe the order in which control tools are used in the barrier (and therefore

the order in which they will be encountered by invading possums) is critical to barrier performance. A third version of the barrier is planned for implementation in October 2016.

Version 2 barrier performance â€“ possums

A note on stoats When the virtual barrier was installed at Bottle Rock in November 2014, stoat defences were not included as we did not believe that the 400 ha peninsula was large enough in relation to stoats' speed or 'typical' home range size (50 â€“ 300 ha) to confirm the area was free of stoats at any point in time. Our suite of control tools for stoats was also extremely limited; we were reliant on TUN200s baited with fresh rabbit meat, Erayz or eggs (or a combination of these). Additionally, the monitoring methods available to us at the time were too insensitive to determine the presence of stoats in the landscape at very low density.

However, the virtual barrier system caught a surprisingly large number of stoats (25) during the 2014 beech mast (inadvertently lured with mice caught in mouse traps inside TUN200 boxes), and another 11 following the rat and possum removal. This gave us some confidence that it would be worthwhile to begin trialing stoat defences at Bottle Rock during 2015/16. Our initial findings from these trials are covered in detail on pages "Stoats map" on page 46â€“53 of this document.

image: A TUN200 trap box with automated-reporting satellite node

Barrier learning and enhancement Rats For many control tools, the likelihood of interaction decreases with each encounter, however we have observed that TUN200 catch rates remain relatively constant throughout the system. This makes the TUN200 a powerful component of the virtual barrier. 22

Effectiveness of food-based lures (percentage of rats intercepted by a TUN200 line at Bottle Rock peninsula)

We have also investigated the required spacing of devices for rats in the barrier to ‘guarantee’ encounter. TUN200s are currently placed at 10 metre spacing along each line on which they are used. A trial carried out along the first defence line (D1) showed that the effectiveness of this line was reduced by 20% when the space between traps was doubled to 20 metres. During 2016/17 a trial is planned to assess whether further efficiency gains can be made by spacing traps at 5 metre intervals along this line.

A productionised version of the TUN200, to be known as the ZIP200, is currently in development, with production scheduled for November 2017. Potential improvements on the current design include a more ‘open’ tunnel entrance to increase the likelihood of interaction (while still excluding weka and other non-target species), consistent floor and trap plate texture, and an increased space between the traps to provide room for a variety of lures and ease of servicing. In

addition, our catch data suggests that the ambient temperature of the steel plate does not reduce catch rates in cooler winter weather. We are currently trialling automated reporting of sprung traps on D1, to enable us to monitor pressure on the system, respond to ‘holes’ caused by clogging of clusters of traps, and assess decay of lure attractiveness over time. This has the potential to significantly reduce labour, especially in combination with an automated lure dispenser. Both of these developments will be components of the productionised ZIP200. Victoria University PhD candidate Michael Jackson developed a novel in-field bioassay1 during winter 2015, using chew cards to assess a range of food lures for both rats and possums. ZIP engaged a Victoria University Masters student, Anni Brumby, to repeat this trial at Bottle Rock peninsula during spring 2015 to test for any seasonal variation to Michael’s results. Michael’s trial found that his ‘standard’ lure for rats (peanut butter) may be outperformed by walnut, milk chocolate, Nutella, and cheese for attractiveness (with no statistically better consumption score). When ZIP replicated this trial, we found that Nutella, Pic’s peanut butter, and roasted, ground soybean performed best. Right: An early prototype of ZIP’s automated food lure dispenser

1. M Jackson, S Hartley & W Linklater (2015) Better food-based baits and lures for invasive rats Rattus spp. and the brushtail possum Trichosurus vulpecula: a bioassay on wild, free-ranging animals, Journal of Pest Science, Volume 89, Issue 2, 479-488

This trial reinforced our belief that a combination of lures is likely to be optimal to intercept as many rats as possible. ZIP has been working with the engineering firm inFact in Christchurch to develop an automated food lure dispenser, for use as a component of the ZIP200 and as a stand-alone unit with potential pre-feeding application. The dispenser is designed to deliver micro doses (0.3 ml) of fresh lure daily into devices (or for pre-feeding purposes) to maximize the effectiveness of traps in the system. The productionised dispenser has a target cost of $30 per unit, and will be compatible with a range of food-based lures.

As at 30 June, we are about to begin field testing our prototype automated lure dispenser. The dispenser will ensure a lure is fresh and constantly available, as currently lures are either rapidly spoiled by mould or consumed by non-targets. It is expected that this development will halve the servicing cost, with future visitation only required to empty the traps, not refresh the lure.

card, with D-block (Diphacinone) toxic bait in the middle of the card. This was designed to enable us to track bait take by species and estimate the contribution of toxins to our barrier system. Unfortunately, this bait station has not performed as we had hoped, with very little tracking or bait take observed. The architecture of this tool appears to have been half as attractive to rats as a TUN200 trap box, when tested with the same lure (Pic’s peanut butter).

While the performance of the ZIPthru during field trials was disappointing, it does indicate that the rat defence system has been performing well, even in the absence of an effective toxin or bait station. Above: ZIPthru prototype bait station with D-block and tracking card

In November 2015, ZIP installed a prototype bait station, the ‘ZIPthru’, into the virtual barrier. The ZIPthru consists of a 700 mm length of rectangular downpipe (with a 50 × 50 mm opening once installed with holding pin) containing an ink tracking

As at 30 June 2016, we are considering whether or not to continue trialling this device in the system. To enable us to analyse the performance of the virtual barrier, any new device brought in to replace the ZIPthru will need to have a mechanism whereby target species bait take can be tracked.

In future, building off the work with Norway rats by Simon Fraser University in Canada2, there is potential for the ship rat bedding lure to be combined with ultrasonic rat pup noises to form a ‘complete’ lure with the sound and smell of a rat nest (which may prove to be effective against both rats and stoats). ZIP has been working with Callaghan Innovation to record high quality ultrasonic rat pup noises for this purpose. Below: Ultrasonic speaker developed by Callaghan Innovation to test the attractiveness of rat pup noises as a lure for rats

Ship rat bedding field trials are currently underway at Bottle Rock, following pen trials carried out by Lincoln University student Oscar Pollard, which indicated that rat bedding may be attractive to ‘lonely’ invading rats. We are currently trialling male rat bedding as a lure in the first line of TUN200s in the virtual barrier, assessing the additive effectiveness of this lure alongside Nutella, as compared to the effectiveness of Nutella alone. Early indications are promising, and a full field trial is proposed for 2016/17. 2. S Takacs, P Kowalski, and G Gries (2016) Natural and synthetic vocalizations of brown rat pups, Rattus norvegicus, enhance attractiveness of bait boxes in laboratory and field experiments. doi: 10.1002/ps.4219

Possums ZIP’s automated reporting leg-hold traps were initially lured using a 90x90mm white corflute chew card nailed to the tree approx. 500mm above the trap platform. This was baited with aniseed possum lure and refreshed every 6 weeks. However, when we observed catch data over time, it became clear that refreshing the lure did little to improve trap effectiveness, and catch rates did not reduce between services.

We have come to believe that the visual ‘flag’ created by the white corflute square is a very powerful attractant, and is itself sufficient to cause possums to investigate leg-hold traps. This could be peculiar to invading animals moving through a new environment, who may be driven by curiosity to investigate any ‘novel’ visual cues that they encounter.

This visual luring observation at Bottle Rock is a particularly significant finding for the Remove and Protect model as it reduces the servicing cost of these traps by removing the need to replace food lured chew cards every 6 weeks.

During 2016/17 we will build on these observations and investigate a range of methods to enhance the effectiveness of the visual lure, including glow-in-the-dark and LED-lit lures.

Above: A visually lured possum leg-hold trap as used at Bottle Rock peninsula

Landcare Research (with support from OSPRI) and Plant & Food have developed a synthetic possum oestrous pheromone lure for possums, which will be field tested in the Bottle Rock virtual barrier during 2016/17.

Defence Line 3 (D3) leghold trap triggers over time

Above: Left-hand axis represents the trap number and distance in metres along the line. Vertical dot/dash line represents a date on which the food lure was refreshed. Note that possum interaction and catch rates appear insensitive to the freshness of the food lure (i.e. capture rates do not increase immediately after refreshing the lure)

Right: ZIPâ€™s prototype leg-hold platform design and 3D-printed model, below, developed in partnership with Motovated Design

The automated reporting leghold trap for possums has proven to be highly effective at Bottle Rock, and as a result we have initiated productionising of these tools to enable efficient utilisation at the next scale site. The Ministry of Primary Industries have approved our live capture, automated reporting system for possums, as compliant with animal welfare legislation.

As a result of this development the cost of servicing the leg-hold trap network has fallen to 5% of the cost of a manually serviced system. We have observed a â€˜funnelâ€™ effect at Bottle Rock whereby a leg-hold trap that has caught a possum has a 1 in 3 chance of catching the next possum to be caught on that line within a 10

day period of the original catch. This is believed to be a result of ground-based scent trails laid by possums as they move through the landscape. As a result of this finding, leg-hold traps were added to the first defence line when the barrier was reconfigured in January 2016, replacing the Trapinator kill traps that had previously been used. To date this effect appears to have further increased the effectiveness of the front line by 5%. No funnel effect has been observed for rats.

A possum wanders towards a line of traps, making a scent trail. It is caught in one trap.

A second possum wanders in, later that night or any time up to 10 nights later. Once it hits the first possum's scent trail, it follows it, directly to the same trap.

The overall effect is as if there is a funnel approximately 200 m wide, lasting 5-10 days, which directs possums into the first trap. Possums approaching the barrier from outside this zone of influence may wander into another trap or not encounter the line at all.

Blending the barrier with predator fencing On 9 June 2016, ZIP officially opened a two hectare predator research enclosure in Lincoln, which was built as part of a broader collaboration with Lincoln University and funded by investment from a group of Dairy companies made up of Fonterra, Synlait, Tatua, Open Country, Westland Milk Products and Miraka. This facility enables us to rapidly test new developments prior to trialling in the field at Bottle Rock peninsula, with a particular emphasis on developments that could enable the Remove and Protect model in rural production areas, such as farms and dairy processing facilities. The Enclosure is 200 metres long and 100 metres wide, and is bisected by a fence at the one-third point. The bisecting fence has an opening 20 metres wide, where we are trialling a range of techniques to defend permanent openings in predator fences, for potential application at road crossings, gateways and/or waterways. During 2015/16 we began to trial a range of deterrents to defend openings in predator fences. Waikato University PhD candidate Bridgette Farnworth has been working alongside the ZIP team at Lincoln to test the effectiveness of light as a deterrent for rats, both in small pen trials and in the

large enclosure. In the large enclosure, a 20 metre wide, 5 metre deep strip of bright light (1,000 lux approx.) was installed to test the motivation of ship rats. An initial trial involving 10 rats released individually into the enclosure has already delivered promising results. Although 8 of the 10 rats did cross the lit zone, the majority did so only after displaying hesitant behaviour, and all 8 entered trap boxes placed in the lit zone.

In a real-world application, all 10 rats would have either been deterred or been caught and killed while attempting to pass through the lit zone. Next we propose to attempt to use light to â€˜steerâ€™ rats away from a lit zone towards the dark. left: Minister of Conservation, Maggie Barry cuts a ribbon at the Opening of ZIPâ€™s predator research enclosure, with ZIP Board Chair Devon McLean on right.

A number of ‘off-the-shelf’ ultrasonic deterrents have also been tested, with little observable effect on ship rat behaviour. During 2016/17, we propose to trial an electric grid system and explore other potential deterrents, including threat of predation. ZIP is also exploring optimising the height of predator fencing (typically two metres high to exclude cats) to exclude just rats, possums and stoats. Reduced height predator fencing is likely to be more socially-acceptable than traditional predator fencing, in areas such as rural production land or along road ways. Below: Animal Behaviour Technician Tom Agnew outlines predator jumping heights near the low-height internal ‘cell’ within ZIP’s large enclosure

Testing carried out to date in the 4 x 4 metre internal ‘cell’ in the large enclosure indicates that stoat jumping heights may not be as great as previously thought. To date, stoats have been unable to jump out where the fence was lowered to 0.8m. Further stoat testing is still required along with evaluating the minimum fence height for rats and possums.

200m

100m

Above: Lighting deterrent trial setup as seen at night. Photo taken from rat release point, represented by purple dot in above diagram.

Detection and response Radio-collared invading rats By early September 2015, after a sustained effort by the ZIP field team, all resident rats had been removed from the Protected Area at Bottle Rock peninsula. To help us design a detection system at Bottle Rock, we needed to learn more about how a ‘lonely’ rat behaves, when it enters an area with no other rats. In other words, we wanted to better understand the movement pattern of an individual invader in space and time, to help ensure early detection and timely removal. Left: ZIP’s first radio-collared rat, ‘Dr Livingstone’

Between July and September 2015, we caught ship rats from an area adjacent to Bottle Rock peninsula, fitted them with VHF transmitters, and released them one at a time into the protected area to see where they went. We then manually tracked each radio collared rat to locate daily den sites.

0m 400m

Rat track Rat release

Dr. Livingstone

Hanno

Calamity Jane

Isabella Bird

Rat den

We found that all four released ship rats behaved quite differently, with a variety of exploratory behaviours exhibited. Only half of the rats were successfully detected by our detection system. We learned that it can be extremely challenging to efficiently detect the lone rat in a large landscape, as those released (after an initial period of exploration) generally adopted a small â€˜home rangeâ€™, in the order of one hectare. Therefore, the intensity of devices required to guarantee detection does not lend itself to economically scale up across large landscapes.

More optimistically, the relatively small home ranges adopted indicate that an individual male or non-pregnant female rat would likely cause minimal ecological damage in an otherwise rat-free area, and that functional extinction is a probable outcome if less than one ship rat is present per, say, 200 hectares. Above: Daily den-to-den movements of four radio-collared rats released at Bottle Rock peninsula between July and September 2015 (manually tracked using VHF)

Detecting ‘Gen One’ – a new strategy Following the variety of behaviours observed during the ‘lonely’ rat releases on Bottle Rock, we revisited our approach to detecting invaders in the Remove and Protect system.

Rather than attempting to efficiently detect individual invaders, we began to consider a different approach. If the invader was alone, infrequent or non-pregnant, then they posed no real threat and could reasonably be expected to die out in typically one year. Consequently, we are now looking to determine whether the dispersal footprint of a first (and potentially second) generation breeding event is both detectable and removable.

Above: A nest of ship rat pups at ZIP’s research facility in Lincoln

In late-September 2015, a pregnant female ship rat fortuitously arrived in the protected area, and a breeding event took place. The initial invader was detected in September 2015, with the last of her offspring trapped in December 2015. The entire Generation One event lasted a total of 90 days, and the invasion ‘footprint’ was estimated to have covered 66 ha. A total of nine kills were recorded and it is likely that this was the size of the litter including the mother. If the typical dispersal footprint of a Generation One event is up to 100 hectares (i.e. 1 km²), we believe that the spacing of primary detection devices could be relatively light (say just one device every 50 ha) and yet still tip us off to its presence.

Detection

Kill

0m 500m

Above: Breeding event at Bottle Rock peninsula, September 2015

We also hypothesise that we could have up to 100 days to detect and remove the first generation of invaders, before the juveniles reach sexual maturity and begin breeding themselves. The bigger ‘footprint’ of an emerging population (as opposed to an individual rat) allows detection to be scalable, although conversely it will require a bigger treatment area for removal.

If this strategy is successful, we could install a very low-density detection system to manage rat incursions at a ‘Remove and Protect’ site, with potential cross application to the management of island and fenced sanctuary incursions. To better understand the ‘footprint’ of a first generation breeding event and our ability to detect it, we are planning an experiment at Bottle Rock whereby we will release a radio collared pregnant female rat into the protected area and observe the spatial and temporal distribution of her emerging offspring.

Rat reinvasion event (Feb-June 2016) From about February 2016, ship rats began to reinvade the protected area at Bottle Rock. We believe this occurred largely as a side-effect of the radio-collared stoat release trials carried out between January and March 2016. To reduce the risk of accidentally killing stoats released on the peninsula before they encountered the virtual barrier, as a precaution we de-activated the majority of the rat traps in the protected area and monitored for any rats using chew cards. We now believe that this may have provided sufficient opportunity for a small number of invading rats to breed within the protected area. Unfortunately, the increase in rat numbers initially went undetected, as the sensitivity of the chew card had been significantly reduced, as a result of a change by the manufacturer to recycled plastic corflute, which had a strong odour that made it less palatable. When this issue was confirmed in June 2016, all chew cards were replaced which resulted in an instant improvement in performance of the detection system. As of June 2016, efforts to remove the newly established population on Bottle Rock continue.

The failure of our high-performing chew card detection tool for rats was not something we had anticipated, and a number of management decisions were made on the assumption that they could be relied upon for early warning of invaders – including closing the DOC 150s in the protected area during the stoat release trial. This incident was a timely reminder of the need to retain a high level of vigilance and the need for redundancy in our detection systems. A number of developments are also in train to enable a quick response to future incidents. For example, devices such as the ‘ZIPtip’ could alert us to the presence of rats within an hour of interaction. Additionally, during 2016/17 we will begin to develop spot-treatment methodologies, which we intend to trial as part of the ‘Gen One’ trial to detect and remove an invading female rat and her offspring.

The response to the reinvasion event at Bottle Rock during 2016 was a good example of both the necessity of early and accurate detection of invaders, and the high level of risk intrinsic in managing a complex ecological system.

Rat kills February 2016

Rat kills April 2016

Rat kills June 2016

Above: A corflute chew card with distinctive rat gnaw marks

Automated detection Chew cards are one of the most sensitive and durable tools right now for detecting rats and possums. They appear sensitive to the level of individual animals if deployed for long enough. Below: A rat triggers the â€˜ZIPtipâ€™ protoype automated detection device during field trials

above: Al Bramley and John Wilks install a ZIPtee detection device for field trial at Bottle Rock

A focus this year has been the development of automated chew card-based detection for rats and possums. Utilising the same transmitter-based engine and cloud based database/ webserver developed for the remote reporting of leg-hold traps, we prototyped a variety of device architectures to exclude weka and mice coupled with a movement sensor; and analytics to screen interference by daytime birds like tauhou (silvereyes). But, false reports caused by wind and rain presented an ongoing challenge. As a result we recently developed a prototype, the ‘ZIPtip’,

which uses a mechanical ‘tipping’ trigger mechanism (rather than a movement sensor), activated by the animal as it climbs up the device to access a lure, which we are confident should reduce the weather interference. This device is now in field testing and early indications are promising. A tunnel architecture detection device, the ‘ZIPtee’, which uses the same tipping mechanism as the arboreal ZIPtip, is also being trialled at Bottle Rock. The advantage of this device is that it can be located on the ground and be inaccessible to non-targets like weka. However further trials are required with both devices to build confidence in their integrity.

Above: Map showing proposed placement of â€˜lightâ€™- detection leg-hold networks at Bottle Rock peninsula

Detecting and removing â€˜lonelyâ€™ roaming possums Possums are very slow breeders, typically producing one young a year, which gives us the luxury of time when it comes to detecting and removing individual invaders. Catch and chew data at Bottle Rock indicates that due to their roaming behaviour at very low densities, invading possums are likely to be relatively easy to detect, using a light network of visually lured, low-interaction tools.

We propose to trial from October 2016, a light deployment of auto-reporting leg-hold traps (one trap every 50 hectares), to intercept invaders in the protected area, including some radio-collared individuals we will release ourselves.

above: Michael Tunnicliff and Duncan Kay at Bottle Rock peninsula

Stoats map

Release

Death

Stoats

First iteration of the stoat virtual barrier and stoat detection Our primary work on stoats this year focussed on the release of eight radio-tagged stoats onto Bottle Rock peninsula, to observe whether they could get out through the barrier (in reverse). This trial reinforced our understanding of their mobility, the attractiveness of oestrous stoat bedding as a â€˜socialâ€™ lure and the sensitivity of cameras at detecting stoats in the landscape. Left & Below: Movements of radio collared stoats released at Bottle Rock during summer 2016

Between January and March 2016, a preliminary investigation of a virtual barrier for stoats was undertaken, comprising four lines of traps and ZIPthru bait stations containing PAPP. This was successful in screening approximately 60% of stoats - all from trapping, with zero activity on the ZIPthrus. With the recent discovery of the effectiveness of an oestrous stoat lure, significant improvement is expected with the next version of the stoat barrier, scheduled for implementation in January 2017.

Stoat ‘social’ lures The team at Lincoln University, led by Elaine Murphy, investigated the attractiveness of oestrous stoat scent as a lure for stoats during 2014/15, and found that bedding material used by oestrous stoats was attractive to over 90% of both male and female stoats during pen trials. This finding has the potential to significantly improve, perhaps even double, the success rate of traps. Large scale field trials are currently underway to determine if this effectiveness is evident in the real world. The attractiveness of oestrous bedding as a stoat lure led us to attempt to synthesize it, working alongside Plant and Food Research. With the support of

the Dairy Industry Investment Group, our two hectare predator-fenced enclosure at Lincoln has enabled rapid evaluation (ten times faster) of the first attempt at synthesis. This first attempt was not successful, due to the chemical complexity of the oestrous stoat smell. As a result we are currently reliant on a limited supply of bedding harvested from female stoats housed at ZIP’s predator research facility. Fortunately, however, the quantity we are able to harvest is likely to be sufficient for deployment at both our current site and our next scale site of approximately 4,000 hectares.

Time spent interacting during pen trials oestrous stoat bedding vs control bedding

Oestrous stoat bedding was also used to lure cameras to detect the eight radio collared stoats released at Bottle Rock. We observed a high level of interest in this lure. Interestingly, the majority of stoats appeared to only visit this lure on a single occasion. While bedding material from a single oestrous female was used at all camera sites, the scent may only be effective once and therefore care may be needed not to impact on the effectiveness of traps e.g. TUN200s, as stoats that have already encountered this lure appear unlikely to interact with it on a subsequent encounter, reducing the likelihood of a catch.

below: Wild stoat interacting with oestrous lure at Bottle Rock (screen shot from video camera footage)

Using cameras to detect stoats In parallel with the stoat releases on Bottle Rock in January 2016, we investigated the sensitivity of cameras as a detection device for stoats. The cameras were placed on a 20 hectare grid and were lured with a chew card filled with rabbit kidney and a small piece of bedding material, harvested from a captive stoat in oestrus. The combination of camera and lure exceeded our expectation, with a median time to detect both male and female stoats following release on the peninsula of 7 days.

Above: A radio-collared stoat ‘caught’ on video camera while investigating a rabbit-baited chew card

This is a significant discovery, as low densities of stoats have been historically very difficult to reliably detect in the landscape. We can now envisage a

Stoats on camera – average time to detection Days in camera'd area to first sighting: {1, 4*, 4*, 5, 5*, 6, 7, 14*} * = killed or escapes before sighted (right censored)

tool that could accurately measure the presence (or absence) of stoats â€“ vital in determining whether an area is free of this predator and in the short term whether our tools are working. We have also been exploring with partners, how to further improve the sensitivity of the camera, by using less intrusive hardware and developing analytics e.g. image recognition, that enables the footage

to be automatically screened for the predator in question. This work has been in collaboration with Grant Ryan (Cacophony Project), Kinopta and Massey University. So given the mobility of stoats and the sensitivity of cameras, a relatively light network of cameras (say one every 50 ha) lured with oestrous stoat smell, could have a very high probability of detecting the presence or absence of stoats in a big landscape.

below: A radio-collared stoat, dyed for easy identification, investigates a rabbit-baited chew card during trials at Bottle Rock

Above: Stoat â€˜pitfallâ€™ trap installed at Bottle Rock peninsula, disguised with foliage and leaf litter

A giant pitfall trap for stoats Working with stoats in the Lincoln enclosure has led to an interesting spin-off discovery. In investigating the minimum height of a predator fence to exclude stoats, we discovered that our internally hooded 4 x 4 metre cell (contained within the larger two hectare enclosure), became a trap for stoats that they could not climb or jump out of. Stoats readily jumped into the cell from outside, presumably expecting

to be able to climb out easily as would generally be the case in their natural environment. As a result, we have built a prototype stoat ‘pitfall’ trap which has just been deployed at Bottle Rock for concept testing. We suspect that this trap could be highly effective, as it represents ‘danger disguised’.

We envisage the pitfall trap could have potential as a removal, detection and response tool for stoats at the next scale. Below: In this sequence, a stoat jumps into the 0.8m high fenced ‘cell’ and is then unable to jump out

Above: Prototype stoat ‘pitfall’ trap

Future direction: Scaling up As the Government takes aim at a predator free New Zealand by 2050, we are beginning to think about how we will go about scaling up our operations. Although at least two years away, we know the next step in scale is part of the roadmap to proving the feasibility of the Remove and Protect model for wide scale deployment. We realise this confidence will only come with successful deployment at a site of approximately 20,000 hectares; however, there are some key interim steps between our current site (400 hectares) and this much larger scale. During 2016/17 we propose to begin investigating potential sites of approximately 4,000 hectares. 54

At this scale, considerable investment is required to establish and maintain a predator free area and it will be a long-term project to restore the area. As a result it is expected that the project will likely be led by the local community. In addition, at this scale we still have a lot to learn, especially about managing stoats, and therefore it will initially need to be a learning site and restoration site combined.

Key criteria to maximise the chance of the Remove and Protect model succeeding at a 4,000 hectare site include: 1. a community committed to restoring their local native biodiversity; 2. an easy shape to defend i.e. a peninsula with a relatively narrow neck; 3. significant existing conservation value; 4. ship rats, stoats and possums as the dominant predator suite; and 5. an accessible ‘barrier zone’ Between now and then, our focus will be on proving the system for rats and possums at Bottle Rock.

To date we are confident we can manage leakage of a virtual barrier to approximately 2% for rats and 5% for possums. For the system to be feasible at a larger scale, we would like to reduce leakage to less than 0.5% for rats and less than 5% for possums (depending on how easy they are to intercept if they breach the barrier). In addition, we need to improve our ability and confidence to remotely detect and respond rapidly to a rat breeding event. And last, but not least, we will be developing the ‘tool box’ to enable efficient initial removal of the predator suite.

Financial summary Founding partners

Investors

Overheads

Operate Bottle Rock

Toxins Future site selection

Research and development

Invasive Behaviour

Synthetic possum pheremone lure

Detection

Other traps

Modelling/analysis Lure dispenser

Collaboration and engagement

Productionise ZIP200

Initial removal

Deterrents Lures

Leg hold trap system

Financial summary and Auditorsâ€™ report ZIPâ€™s 2015/16 financial statements have been prepared by The Business Advisory Group Limited and have been audited by PwC. If you wish to view these financial statements please visit charities.govt.nz for a full set of disclosure financial statements.

We have provided a summary of the funding and expenditure in 2015/16. We would also like to take this opportunity to thank Caroline Wallace for her efficient bookkeeping and diligent management of ZIPâ€™s Accounts during the year.