ZIP Annual Report 2017-18

Annual Report 2017–18

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ABOVE:

‘Michael’s Creek’, Bottle Rock peninsula field development site (RORY HARNDEN)

FRONT AND BACK COVER:

View down the Perth River valley – the site of our large-scale trial of the Remove and Protect model (refer pp. 12–14) (CHAD COTTLE)

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Contents Forewords

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Devon McLean, Board Chair • Al Bramley, Chief Executive

ZIP Board

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The Challenge

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ZIP Team

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Our Approach

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The 2017–18 Work Programme

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Barrier Projects Highlight One: Rivers as Barriers to Possums Initial Removal Projects Highlight Two: Successful Removal of Possums and Rats – Jackson/Arawhata Trial Detect and Respond Projects Highlight Three: Understanding the Dispersal Footprint of Ship Rats Lure Projects

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Future Directions

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Founding Partners and Funders

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Founding partners • Funders

Financial Summary

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Predator Key Facts

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Glossary

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Forewords Devon McLean Board Chair I am delighted to present this, the fourth ZIP Annual Report, at a time of significant and growing momentum toward a predator-free New Zealand.

New Zealanders are increasingly aware of the responsibility – and opportunity – we all have to work together to halt, and ultimately reverse, the decline of our unique and wild natural heritage.

During the last year, the collective action of national and local Government, the commercial and philanthropic sectors, and the broader New Zealand community, has continued to grow.

In addition, ZIP has continued to make great strides toward enabling the ‘Remove and Protect’ model for the complete, and permanent, removal of possums, rats and stoats from large mainland areas.

Increasingly, the tools and capability being developed by ZIP, several of which are detailed in this report, are expected to help enable the success of many of these initiatives, including Predator Free Hawkes Bay, Taranaki Mounga, Predator Free Taranaki, and Predator Free Wellington.

I would like to thank our partners the NEXT Foundation, Department of Conservation, Morgan Foundation, Jasmine Social Investments and Predator Free 2050 Limited, for their continued support of ZIP, along with Open Country Dairy, Fonterra, Synlait, Tatua, Westland Milk Products and Miraka, who supported a suite of projects between November 2015 and October 2017. I’d also like to acknowledge the ZIP Board of Directors for their time, enthusiasm and wise counsel.

Finally, my thanks and congratulations to Al Bramley and to the entire ZIP team who continue to show huge commitment to the task, resilience in the face of a continually evolving research environment, and a thirst for new ways to solve these wicked challenges.

ABOVE:

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ZIP Board Chair Devon McLean (RORY HARNDEN)

FO R E WO R DS

Al Bramley Chief Executive During the last 12 months we have continued to develop the Remove and Protect model for the complete, and permanent, removal of possums, rats and stoats from large mainland areas. Results from our programme of work during this time have lent support to, and increased our confidence in, this targeted approach.

In 2017, we completed another ‘1080 to Zero’ trial in South Westland, which successfully removed all possums – and ship rats – from a forested site of 2,300 hectares. You can read more about this trial on pp. 23–27.

Alongside this, we ran a second ‘Gen One’ detection trial (described on pp. 32–35), which determined the spatial ‘footprint’ of a litter of ship rat pups, and gave us confidence in the feasibility of our detection strategy for ship rats. We also ran a trial in the Remutaka Forest Park, near Wellington, which confirmed the effectiveness of rivers as barriers to possum migration (this trial is described on pp. 19–20).

The information provided by these trials has allowed us to embark upon a programme of research and development work in the Perth River valley (South Westland) through which we aim to completely, and permanently, remove possums from a site of 12,000 hectares. We will also seek to develop this approach for ship rats and stoats.

This will be the first time such an attempt has been made on the New Zealand mainland, at such a large scale, without the use of fences, and the results are expected to help bring New Zealand one step closer to achieving predator-free status.

ABOVE:

ZIP Chief Executive Al Bramley

(RORY HARNDEN)

This year we also began to develop predator management solutions for an increasingly diverse range of landscapes, supporting initiatives led by NEXT Foundation and Regional Councils to remove possums from farming landscapes, and providing advice to Predator Free 2050 Limited on a range of emerging projects.

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There have also been a few surprises along the way! Our work to develop the ‘ZIP200’ rat and stoat trap (using a run-though architecture that our testing indicated was significantly more effective at catching ship rats than a standard box) ended abruptly in early 2018, when testing revealed that a significant number of ship rats were able to trigger the trap without being caught. We have subsequently initiated a project to develop a highly effective ‘tunnel’ trap, the ‘ZIPinn’, which will undergo further development and testing during 2018–19.

I’d like to thank our founding partners, DOC and NEXT Foundation, both of whom provide support that goes far beyond their financial contribution to our work. The exemplary leadership provided by the NEXT Foundation enables us to remain tightly focused and agile. Our colleagues at the Department of Conservation provide a high level of technical and operational support, and advice on proposed projects, often challenging us to sharpen our critical thinking to ensure our approach is sound.

I’m also very grateful for the advice and support of representatives of Te Rūnanga o Makaawhio, without which our work in South Westland would not have been possible.

I’d also like to thank our funders Jasmine Social Investments, Morgan Foundation and Predator Free 2050 Limited, for their continued support.

This year we completed a portfolio of projects jointly funded by six dairy companies – Open Country Dairy, Fonterra, Synlait, Tatua, Westland Milk Products and Miraka – between November 2015 and October 2017. Their support enabled us to make significant progress toward developing the Remove and Protect model, particularly for application in a rural context.

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A wide range of organisations and individuals have helped make our work possible, and keep our team safe, including (but certainly not limited to) Department of Conservation, Lincoln University, Manaaki Whenua-Landcare Research, Hawkes Bay Regional Council, Taranaki Regional Council, OSPRI, Orillion, Pest Control Research, Game Animal Council, New Zealand Deerstalkers Association, Lincoln University Animal Ethics Committee, Predator Free New Zealand Trust, Media Fix, VISIONCO, Anderson Helicopters, Tasman Pest Control Limited, Sounds Air, Cougar Line, Fox/ Franz Heli Services, Zealandia Eco Sanctuary, Willowbank Wildlife Reserve, Spark Ventures, Cacophony Project, Resolution Bay Cabins, Pic’s Peanut Butter, Goodnature, Tararua Tramping Club, Triple One Care, AsureQuality, Harris Training Services, Training Ventures, Search and Rescue Institute New Zealand, and a large number of engineering firms (listed on p. 14) and contractors who have assisted us in many and varied ways.

And to everyone else who has supported and encouraged us during the last year – thank you!

BELOW:

Some of the Department of Conservation staff who provide guidance and advice to our programme of work, on-site in the Perth River research area.

L–R: Martin Kessick (DDG Biodiversity), Mark Davies (Director - Operations, Western South Island) and Amber Bill (Director - Threats, Biodiversity Group). (AL BRAMLEY)

ABOVE:

L-R: ZIP Board Chair Devon McLean, Chief Executive Al Bramley, Board Director David Flacks, and DOC Senior Liaison Mike Slater, at Perth River research area. Absent: Board Director Charles Daugherty (KRISTIN KENNEDY)

ZIP Board The ZIP Board met four times during 2017–18, including one visit to the Perth River research area, South Westland.

The ZIP Board is chaired by Devon McLean, and includes Charles Daugherty and David Flacks as Directors.

Senior liaison with DOC is through Mike Slater (Deputy Director-General – Operations). Mike is not a Board Director, but represents the Department as a partner at Board meetings.

Z IP BOARD

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ABOVE:

Kakaruwai (South Island robin) (CHAD COTTLE)

The Challenge Possums, rats and stoats are understood to be the main agents of decline for many of our vulnerable native species, collectively devouring an estimated 68,000 birds, chicks and eggs, every night – along with reptiles and invertebrates (such as wētā), flowers, fruit and other vegetation.

As outlined in the Parliamentary Commissioner for the Environment’s 2017 report ‘Taonga of an Island Nation’, of the 168 remaining species of native birds in New Zealand, 135 are in some trouble (of which 54 are in serious trouble).

Many of New Zealand’s unique and charismatic birds have now largely disappeared from the New Zealand mainland.

Some have disappeared forever, and some, like the tīeke, hihi and kakapō, have been brought back from the brink of extinction only through the intensive efforts of conservationists to relocate them to predator-free environments such as offshore islands and fenced sanctuaries.

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T H E C H A L L E N GE

In fact, New Zealanders are world leaders in creating such environments, eradicating predators from over 100 islands in New Zealand waters; most recently mice have been eradicated from the 2,100 hectare Antipodes Islands through a joint initiative between DOC, the Morgan Foundation, WWF-New Zealand, Island Conservation and public supporters.

New Zealanders have also lent expertise to many international island eradications, including the recent removal of rats from 108,700 hectare South Georgia Island.

However, it is not yet possible to completely, and permanently, remove introduced predators from large mainland areas (without fences). Mainland control of possums, rats and stoats is currently limited by three key factors: 1. Without border defences, the ongoing invasion of these predators, and the speed of their population growth, constrains the ability of the native biodiversity to achieve a high level of indigenous naturalness (or ‘ecological integrity’); 2. The ongoing cost of current methods restricts the scale at which they are able to be deployed; and 3. Target predators have the potential to become resistant to toxins through their repeated and ongoing use.

ZIP’s mission is to rapidly develop the new knowledge and operationally-ready, socially acceptable methods required to completely remove possums, rats and stoats from large mainland areas and prevent their re-establishment – a model we call ‘Remove and Protect’.

Achieving this will enable communities and authorities to restore native biodiversity to a level that could (in time) rival that of predator-free offshore islands, and eliminate the economic impacts of these predators. It will also reduce New Zealand’s dependence on the repeated large-scale application of toxins. And it will bring New Zealand closer to achieving predator-free status.

ZIP was not established to develop new biological or genetic methods such as spreading infertility, using a virus, gene drive technology, or otherwise manipulating genes to cause possums, rats or stoats to decline to extinction. These techniques appear to have potential for predator control in New Zealand, but are unlikely to be available for wide-scale deployment for many years.

In contrast, the methods used under the Remove and Protect model are largely incremental advances on what is already available and generally considered to be socially acceptable. That said, some of the methods ZIP is developing to lure and detect predators would almost certainly be useful under a biological or genetic model of predator control.

BELOW:

Formerly widespread and common throughout New Zealand, tīeke (saddlebacks) are now largely confined to predator-free islands and fenced sanctuaries due to their extreme vulnerability to introduced predators such as rats and stoats. If successful, the Remove and Protect model could enable these birds to once again thrive on the mainland.

(DAVID COOK WILDLIFE PHOTOGRAPHY)

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CHIEF EXECUTIVE

Al Bramley

EXECUTIVE ASSISTANT

Kristin Kennedy

OPERATIONS DIRECTOR

Duncan Kay

FIELD TEAM SITE LEAD (BOTTLE ROCK)

FIELD TEAM SITE LEAD (PERTH RIVER VALLEY)

PREDATOR BEHAVIOUR TEAM LEAD

Nate St Hill

Courtney Hamblin

Tom Agnew

FIELD RANGER

FIELD RANGER

Michael Tunnicliff

Matt Chisnall

FIELD RANGER

FIELD RANGER

Chelsea Price

Chad Cottle

FIELD RANGER

FIELD RANGER

Ben Blain

Klayre Cunnew

FIELD RANGER

FIELD RANGER

Robina Brock

Tim Dawe

FIELD RANGER

FIELD RANGER

Alex Edwards

Piper Douglas

CASUAL FIELD RANGER

CASUAL FIELD RANGER

Craig Nicholas

Kim Newton

CASUAL FIELD RANGER

Reuben Lane

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ZIP TEAM

PREDATOR TECHNICIAN (0.25 FTE)

Becky Clements PREDATOR TECHNICIAN (0.25 FTE)

Katie Coster

INNOVATION DIRECTOR

Phil Bell

PREDATOR SYSTEMS MODELLER

STRATEGY AND SYSTEMS DIRECTOR

Nick Mulgan

Joseph Arand

PREDATOR ECOLOGIST

Helen Nathan

ENGINEERING DIRECTOR

John Wilks

COMMUNICATIONS AND DEVELOPMENT LEAD

Susannah Aitken

PREDATOR ECOLOGIST

Maggie Nichols

FINANCIAL ADMINISTRATOR (0.3 FTE)

Caroline Wallace

SCIENCE AND TECHNICAL RANGER

Briar Cook SCIENCE ADVISOR (0.2 FTE)

Elaine Murphy SCIENCE ADVISOR (0.1 FTE)

James Russell

ZIP Team People—our team, conservation partners and other stakeholders—are always our number one priority, without exception. We are caring, connected, empowered and innovative.

Carefully managing our health, safety and well-being, as well as that of our partners and stakeholders, is critical to successfully working toward our research and development goals.

—Zero Invasive Predators Ltd (ZIP) – ‘Our Team Culture’

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Since our last annual report, the ZIP team has continued to grow, and there have been some changes to sites and roles. The organisation chart above is current as at 30 June 2018.

Twice-yearly meetings are also held to enable the whole team to connect as a group and update one another on the work programme at each site.

This year we welcomed 16 new team members (a mix of permanent and fixed-term staff, and casual contractors), and farewelled four permanent team members: Pete Morresey (Bottle Rock Field Team Lead), Tim Sjoberg (Taranaki/ Jackson-Arawhata Field Team Lead), Ripley Dean (Jackson-Arawhata/ Perth River Field Team Lead) and Oscar Pollard (Animal Behaviour Technician/ Field Ranger).

We are pleased to see former team members now contributing to other predator-free projects and restoration initiatives.

Much of our work involves long distance travel to remote field sites, where the weather is frequently wet and cold, and the terrain comprises steep and slippery hill and mountain slopes and challenging stream and river crossings. The Perth River research area established this year brings the added challenge of snow, ice and avalanche risk.

We have continued to build and maintain personal connections across the ZIP team, by enabling all staff to join the work at our field sites, the predator behaviour facility (at Lincoln) and the ZIP office (in Wellington, adjacent to Zealandia Sanctuary).

During 2017–18, our staff worked for approximately 3,100 days in the field.

We recorded five work-place incidents, comprising three injuries, none of which resulted in permanent harm (i.e. a serious wasp sting, one partial and temporary dislocation, and one neck strain), one late check-in, and an item that fell off a vehicle. We investigated each incident, and shared what we learned across the team to minimise the risk of it happening again.

BELOW:

Upper part of the Barlow River catchment, Perth River research area (MICHAEL TUNNICLIFF)

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OPPOSITE:

Perth River research area, view upstream near Scone Hut (CHAD COTTLE)

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Our Approach The Remove and Protect Model comprises four broad categories of work:

Category of Work

Establish and maintain barriers to prevent reinvasion by possums, rats and stoats Initially remove possums, rats and stoats from an area protected by the barrier(s)

Lure possums, rats and stoats to eat baits and interact with detection devices

Detect and remove any predators that survive the initial removal or breach the barrier

Our broad approach is to develop and deploy the model over increasingly larger field sites, as we learn what works and what doesn’t.

One of our first actions in 2015 was to establish a 440 hectare field development site at Bottle Rock Peninsula, which we still operate. The Bottle Rock site is where we trial tools and techniques in a relatively small field area, in order to test and refine their readiness to be deployed at larger sites.

BELOW:

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To date, we have largely focused on possums and ship rats at Bottle Rock, because their home ranges and dispersive abilities are more suited to research at a site of this size.

Stoats, in comparison, are much more mobile (with home ranges typically between 100–200 hectares, and an ability to disperse many kilometres in a couple of days), and therefore require very large field sites to develop interception methods. That said, with an eye to the future, we have begun to investigate methods to lure and detect stoats.

View across Resolution Bay to Bottle Rock peninsula field development site (CHAD COTTLE)

O U R A P P R OACH

ABOVE:

Moody weather at Bottle Rock peninsula field development site (MICHAEL TUNNICLIFF)

In 2017–18 we continued to test our ability to completely remove possums and ship rats from large areas, at a temporary field site on the confluence of the Jackson and Arawhata Rivers, South Westland. A ‘core’ of 400 hectares within a 2,300 hectare treatment zone was intensively monitored to confirm freedom from possums and ship rats (you can read more about this trial on pp. 23–27). Alongside this work, we carried out a trial that resulted in our first confirmed dispersal distances of juvenile ship rats – providing critical information for the development of efficient ship rat detection networks, and rapid removal techniques (more about this on pp. 32–35).

With the support of DOC and OSPRI, we also completed a trial at a temporary site in the Orongorongo River catchment (Remutaka Forest Park), to test the effectiveness of rivers as natural barriers to possums. This trial is described in more detail on pp. 19–20.

Based on the results of these trials, we began a programme of research and development work at a 12,000 hectare site in the Perth River valley, South Westland. At this site we are further developing an approach to completely, and permanently, remove introduced predators from a large-scale area that includes natural lowland to alpine ecosystems. Possums are the initial focus of the research, but the programme will also seek to develop the approach for ship rats and stoats. Our primary focus at this site during 2017–18 was establishing the infrastructure required to service the programme of work. Snow and weather conditions, and the discovery of possums persisting under deep snow, reduced our confidence in the likelihood of the predator removal operation originally scheduled for winter 2018 to completely remove introduced predators; the operation is now scheduled to be carried out from early 2019.

In addition to the work carried out at our field development sites, we are researching lures, tools and techniques at a predator behaviour research facility in Lincoln, which we opened in June 2016. This facility enables us to rapidly test potential ideas, and refine them, before trialling developments that show promise at field development sites. It also enables us to quickly terminate ideas that fail to perform as anticipated. This facility also provides students with useful work experience in predator management and conservation.

LEFT:

Upper part of the Barlow River catchment, within the Perth River research area (CHAD COTTLE)

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Engineering (automated lure dispenser manufacture and trap parts fabrication), Contour Engineering (precision machined parts), Nautech Electronics (motor drivers), ASL Industries (automated lure dispenser assembly and LoRa base stations), Equiptech (predator gate), Strata Group (predator gate), Pestproof Fences (low-height predator fencing), Human Dynamo Workshop and Axis (rapid prototyping plastic and ply traps and detection devices), as well as many others who’ve supported us in various crucial ways over the past year.

ABOVE:

ZIP Principal Engineer John Wilks installing a prototype rat and stoat detection device at Bottle Rock peninsula (AL BRAMLEY)

We work closely with a range of engineering firms to test the feasibility of manufacturing new devices and, once the development phase is completed, to actually manufacture them.

During 2017–18 these included Motovated Design and Analysis (plastic leg-hold trap platform, ZIPinn trap design and low-height predator fencing), Talbot Technologies (rat and stoat trap housings and plastic leg-hold trap platform), Action Plastics (automated lure dispenser plastic mouldings), Nodetech (embedded firmware for all LoRa radio and lure devices), Integrated Mapping (databases and web server management systems), inFact (automated lure dispenser, LoRa radio nodes and base stations), Brush Technology (electronic detection and sound lures), ENI BELOW:

Part of our process to develop new methods involves anticipating whether the method could have potential adverse impacts on native biodiversity, and addressing any concerns.

In general, ZIP does not measure the benefit to native biodiversity of any new predator management method, because it’s widely known that, in most cases, removing possums, rats and stoats from natural ecosystems will result in significant beneficial conservation outcomes. Our research timeframes are invariably shorter than ecological studies of New Zealand’s indigenous biodiversity. That’s largely because our focus is on whether or not a technique either killed or detected possums, rats or stoats, which are results that can be quickly determined.

However, given the long-term nature of the Perth River research and development programme we intend to monitor the outcomes of the planned predator removal using key indicator species and techniques.

Kea being banded and radio-tagged at Perverse Creek Tahr Camp, Perth River research area, to monitor outcomes of Remove and Protect trial (CHAD COTTLE)

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ABOVE:

Robina Brock, Field Ranger, installing a prototype automated lure dispenser at Bottle Rock peninsula field development site (BRIAR COOK)

The 2017–18 Work Programme The main knowledge/tool gaps that we planned to address in 2017–18, and the results of the work, are outlined in the following tables. Three of these projects are highlighted in more detail in this report, and some of the projects are also described on our website (zip.org.nz).

WORK PROGRA M M E

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Barrier Projects Knowledge/Tool Gap

Project

Results

The virtual barrier we have developed does not yet intercept 95% of possums and 99% of ship rats.

Install a network of self-resetting A24 traps to suppress rats before they reach the virtual barrier, with the aim of reducing pressure on the barrier and therefore overall ‘leakage’ into the protected area

A network of four lines of A24 traps at 50m x 50m spacings was found to have a similar catch rate to 1 line of ‘TUN200’ trap boxes at 10m spacings (as in our ‘virtual barrier’ setup).

Investigate whether adding a bungee link to possum leghold trap chains reduces the rate of escapes

The addition of a short length of bungee cord to chains in September 2017 reduced possum escapes from raised set leghold traps with ramps from approximately 5% [3%, 9%] to less than 1% [0.1%, 3.2%].

Change the barrier at Bottle Rock to improve its effectiveness

All possum traps in the virtual barrier were upgraded with ramps and bungee cords by the end of March 2018.

This is the target that we think is needed for the Remove and Protect Model to be cost-efficient in the absence of natural barriers.

Development of the virtual barrier is an ongoing challenge, and we learn by trying a version and then measuring the results.

Although successful at reducing residential ship rat populations, we found that a network of A24 traps at this spacing is unlikely to be effective at intercepting invaders.

Between July 2017 and June 2018, possum ‘leakage’ through the virtual barrier averaged 14% [10%, 18%]. Leakage is measured on the basis of the number of animals caught behind the barrier. Leakage during 2017–18 was higher than that observed during 2016–17, primarily because we ran a number of trials that reduced the effectiveness of the barrier. Fortunately, we are now catching possums faster than ever before when they enter the protected area, due to the improvements to our lean detection system in March 2018 (ref. p. 29).

The lure in all rat traps in the virtual barrier was changed to Pics peanut butter, the most high-performing food-based lure tested to date. However, performance of the rat barrier remains difficult to measure, due to the persistence of a small population of rats beyond the barrier.

RIGHT:

The braided Orongorongo River, Remutaka Forest Park, that resisted possum migration during our trial in 2017 (BRIAR COOK)

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Knowledge/Tool Gap

Project

Results

The effectiveness of rivers as natural barriers to the movement of possums and rats is uncertain.

Work with OSPRI to complete an investigation in the Orongorongo River catchment of the effectiveness of a small, braided river as a natural barrier to possums

Ref. Highlight 1 (pp. 19–20)

Initiate an assessment in the Perth River catchment of the effectiveness of rivers as a natural barrier to rats

Trial site established along 3.2 km stretch of the Perth River, for assessment during 2018–19.

Develop a gate that prevents possums, rats and stoats from crossing bridges, without preventing human access

Gate installed on Scone River Bridge in the Perth River research area.

If rivers are a good barrier, then this may influence the boundaries of large mainland areas targeted for possum and rat ‘Remove and Protect’ implementation.

Some anecdotal evidence exists that predators may cross rivers by utilising back-country swing bridges

Automatic lure dispensers containing a bio-marker (rhodamine B) were installed on one side of the river. At least 90% of the rats on that side of the river have been found to have ingested the bio-marker.

Currently undergoing assessment; no leakage of predators observed to date.

RIGHT:

Predator gate to prevent possums, rats and stoats crossing Scone River Bridge (AL BRAMLEY)

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Knowledge/Tool Gap

Project

Results

Can we improve the effectiveness and safety of the standard DOC200 kill trap?

Develop a more effective, easier to clean and safer version of the standard DOC200 kill trap

Testing of the prototype ‘ZIP200’ tunnel trap revealed that a significant number of ship rats were able to trigger the trap without being caught.

Investigate the ability of an electric grid to deter possums, rats and stoats

Trials at Lincoln found that 19/20 stoats and 21/21 possums were deterred by the electrified grid when set at a voltage of 8kV. The grid was not, however, effective at deterring ship rats in its current design.

Investigate how high fences need to be to be a barrier to possums, rats and stoats

Trials at Lincoln found that a 1.1 m high predator fence (with standard capping and mesh) contained 19/20 stoats, 20/21 possums and 20/20 rats.

The Poutiri Ao ō Tāne Project in Hawkes Bay discovered that a single set run through trap was 1.5 times (95% confidence interval, 1.2 to 1.8) more effective at trapping ship rats than a standard single set DOC200 box (p value for equality of <0.001).

We subsequently initiated a project to develop a highly effective trap, the ‘ZIPinn’, which will undergo further development and testing during 2018–19.

One of our rangers is struck by the kill bar while servicing our TUN200 traps about once every 5,000 traps serviced.

There are no tools to prevent possums, rats and stoats from passing through openings in fence barriers.

In agricultural or urban environments, predator fences are likely to have gaps (e.g. to enable vehicles to pass through).

Does a predator fence need to be the standard 1.8 metre height, if feral cats are not part of the target predator suite?

A low height predator fence could make this tool more socially acceptable, affordable and able to be used in more places.

RIGHT:

Electric grid trial setup, Lincoln (AL BRAMLEY)

RIGHT:

Low-height predator fence trial pen, Lincoln (RORY HARNDEN)

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We envisage that this system may have application as a means to protect permanent openings in fences, when combined with a brightly lit zone to ‘steer’ rats into trap boxes (ref. 2016–17 Annual Report).

A prototype low height (1.1 m high) predator fence will be built and tested in the Aoraki region in 2018–19. We are also investigating options for more efficiently manufacturing and installing predator fences.

Highlight one RIVERS AS BARRIERS TO POSSUMS

Knowledge/Tool Gap There is some anecdotal evidence to suggest that possum migration across landscapes is slowed by natural features, such as rivers and high mountain ranges. If we were able to confirm that these features really do halt or greatly slow down the migration of possums, then this new knowledge would broaden the range of sites where the Remove and Protect model of possum management could be applied across New Zealand. Natural barriers may also be cheaper to maintain and reinforce than a virtual barrier.

Method Between August and October 2017, ZIP ran a trial in the Orongorongo Valley (Remutaka Forest Park), to determine how effectively this relatively small braided river prevents possum migration.

We became aware that a 1080 operation was being planned by OSPRI across both sides of the Orongorongo River in Remutaka Forest Park, in order to control possums (which pass on bovine tuberculosis). This operation presented an opportunity to measure how effectively a relatively small river slows possum migration, and so we proposed to OSPRI and the Department of Conservation that an exclusion zone be established within the 1080 treatment zone as part of a trial to do this. OSPRI and DOC agreed to our proposal, and so a 250 hectare zone was excluded from the aerial 1080 operation carried out on 30 July 2017. The exclusion zone (an area without 1080 baiting) covered a 4 kilometre stretch of land on the true right side of the Orongorongo River.

When consumed by animals, pyranine stains the stomach and intestinal tract and appears as a vibrant green fluorescence (or ‘glow’) when viewed under ultra-violet (UV) light (see below).

Each week, a zone in the lower half of the exclusion block (shown in light green below) was aerially sown with non-toxic cereal pellets dyed with pyranine, and the same pyranine bait was also deployed by hand along the true right edge of the Orongorongo River, to ensure that possums received continuous exposure to the bio-marker.

We installed possum kill traps at 20m spacing along the north, west and southern boundaries of the exclusion zone, to gain a baseline measurement for possum movement across land from the pyranine sowing area. This line of traps (known as the ‘containment line’) was checked weekly.

We also installed a network of automated reporting leghold traps at 20m spacing along the 4WD track on the true left side of the Orongorongo River, to intercept any possums that had crossed the river from the exclusion zone (or had survived the aerial 1080 operation on the true left side of the river). This network was operated in accordance with the MPI Guidelines for good practice when remotely monitoring live capture traps for vertebrates.

BELOW:

Pyranine glow (under UV light) of the intestines of a possum (HAMISH HOWARD)

Our trial was carried out over a period of nine weeks. During this time, we (i) used a non-toxic bio-marker called pyranine to mark possums within the exclusion zone, and (ii) captured possums using kill traps on the ridge top boundary of the exclusion zone and leg-hold traps on the ‘other’ (true left) side of the river.

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Each possum caught in the traps was examined externally and internally for the presence of pyranine using a UV black light.

Results We caught 82 possums marked with pyranine on the upper edge of the containment line (see previous page). In order to have been marked with pyranine, all of these â&#x20AC;&#x2DC;glowingâ&#x20AC;&#x2122; possums must have moved uphill for at least 300 metres (i.e. from the nearest edge of the zone sowed with pyranine).

None of the 44 possums we caught on the line of leg-hold traps on the true left side of the river were marked with pyranine. The location where these animals were caught suggests that they survived the 1080 treatment because they were mostly in small exclusion zones established around huts.

BELOW:Â Comparison

of glowing and non-glowing possum catches on the top section of the containment line, and the leghold line across the river. The river flows from right to left. (NICK MULGAN)

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Discussion This result provides a strong indication that the Orongorongo River was acting as a barrier to possum movement during the course of this trial.

Even though the Orongorongo River is not a large, deep, or fast flowing river, it proved to be a barrier for possums during our trial. The results of this trial support the historical anecdotal evidence that rivers are indeed a very good barrier to possum migration (although certainly not an impenetrable barrier).

This result has encouraged us to consider rivers as components of barrier systems when identifying and evaluating large-scale sites to demonstrate the Remove and Protect model of possum management.

This project is also described as a Finding and associated technical report on the ZIP website, zip.org.nz

Initial Removal Projects Knowledge/Tool Gap

Project

Results

The current aerial 1080 prescription to control possums and rats over large areas does not completely remove them.

Develop and test a new approach to completely remove possums and rats through the aerial application of 1080 at a test site in South Westland

Ref. Highlight 2 (pp. 23–27)

Use a bio-marker (pyranine) to assess kea interaction with cereal baits

Confirmed that pyranine can be used to effectively bio-mark kea and provide an indication of interaction with baits.

Initiate a project to assess survivorship of kea through a ‘1080 to Zero’ operation

30 kea within the Perth River research area have been fitted with radio transmitters, to enable monitoring of any mortality, as well as survivorship and breeding success of adult females following the removal of predators. We estimate that there are 75–100 kea in the research area (more than kea experts initially expected).

Initiate a project to assess survivorship of rock wren through a ‘1080 to Zero’ operation

With the assistance of DOC staff, we have started to visually survey rock wren numbers in selected parts of the alpine zone both within and outside the aerial baiting area of the Perth River research area.

These surveys will be repeated after each of the two applications of the toxic bait (snow level allowing). The results to date indicate that there are about 100 rock wren across the monitored sites.

Initiate a project to assess survivorship of whio through a ‘1080 to Zero’ operation, following our work on Taranaki Mounga in 2015–16 (ref. p.28)

The main rivers bordering, and within, the Perth River research area were aerially surveyed in June 2018. 6 whio were recorded.

In addition, 8 whio have been recorded by rangers during ad hoc surveys between January and June 2018. These numbers align with the low density population estimated in the area. Additionally, field rangers are keeping an ongoing record of any whio sightings that occur during the course of their daily work.

This knowledge gap compromises the ecological outcomes of the operation and generates significant ongoing control costs.

The potential risk to ‘non-target’ species of the 1080 to Zero approach is not well understood.

21

Knowledge/Tool Gap

Project

Results

Initiate a project to assess survivorship of tahr through a ‘1080 to Zero’ operation

A project has been developed by the Game Animal Council, in association with ZIP, New Zealand Deerstalker Association, Professional Hunting Guides Association, and DOC. 21 tahr were radio-collared within the Perth River research area.

Two subsequent monitoring ‘sweeps’ using Sky Ranger have confirmed the highly mobile nature of tahr, with 6 and 7 of the radio-collared tahr found outside the 12,000 hectare research area during the first and second sweep, respectively.

RIGHT:

Peanut butter-lured coreflute ‘chew card’ showing rat presence at Bottle Rock Peninsula (MICHAEL TUNNICLIFF)

It is unknown whether a ground-based toolset can result in complete removal of rats at 400 hectare scale.

A small population of rats is persisting on Bottle Rock peninsula, and compromising our ability to measure effectiveness of the virtual barrier.

22

Attempt to remove remaining rats from Bottle Rock peninsula without the use of aerial toxins or brodifacoum in bait stations

In February 2018, after five months of intensive effort, the decision was made to bring the ground-based re-eradication project to an end, without resulting in eradication. We spent approximately $200/ha trying to achieve eradication.

This process illustrated the limitations of the current toolset of ground-based traps and toxins, and reinforced the need for real-time (or as close as possible) notification of rat presence (i.e. the value of automated reporting traps and/ or detection devices).

We determined that it is very, very difficult to remove a small population of rats from a relatively small (400 ha) area using bait stations and traps (i.e. without the use of aerial toxins), even when the removal project is carried-out by a highly skilled field team.

ABOVE:

View towards Jackson-Arawhata trial site (top right of image) (DAVE KWANT)

Highlight two SUCCESSFUL REMOVAL OF POSSUMS AND RATS – JACKSON/ARAWHATA TRIAL

Knowledge/Tool Gap

A Modified Approach

Aerially applied 1080 is successfully used on the New Zealand mainland to ‘suppress’ possums and rats for conservation and disease management purposes, by suppressing populations to very low numbers. However, because standard 1080 operations do not remove all target individuals, and reinvasion back into those sites is not managed, predator populations recover and these operations must be repeated on a cyclical and ongoing basis (typically every 3–5 years) to sustain the benefits of the predator control.

ZIP has been investigating the potential for a new method of aerially applying 1080 to result in complete removal of possums and rats in forested terrain. We developed the initial modified approach in consultation with experts from DOC, OSPRI and Manaaki Whenua - Landcare Research.

23

In summary, the approach comprises prefeeding the area twice with non-toxic baits, overlapping the sowing of both prefeed and toxic baits to eliminate the likelihood of gaps, and using twice the amount of toxin compared to a standard 1080 operation. If this approach does not result in complete removal, the treatment may be repeated a second time.

The approach requires no zones to be excluded from the treatment area.

In 2016–17 we worked with the Department of Conservation (DOC) to trial the modified technique at a 1,600 hectare block on Taranaki Mounga (Egmont National Park), which removed all possums, and the majority of rats (refer to the ZIP 2016–17 Annual Report for further details), using a single treatment of aerial 1080. This result was promising enough for us to run a similar trial in South Westland during 2017–18.

ABOVE:

Helicopter delivering bait during predator removal operation (MICHAEL TUNNICLIFF)

Method Prefeed bait was applied by GPS-guided helicopter over the entire block on 5 June 2017, followed by the second application on 16 June.

Prefeed is a non-toxic version of the bait which ‘teaches’ possums and rats that this ‘food’ is safe, so that they more readily consume the toxic bait once applied.

As part of the planning for this project, we were advised that juvenile kea were the non-target species most at risk of consuming toxic bait. Consequently, we contracted a specialist to survey the block for the presence of kea after the prefeed application. No flocks of juvenile kea were observed, with just 5 birds (2 adults and 3 sub-adults) seen.

ABOVE:

Jackson-Arawhata trial site

(MICHAEL TUNNICLIFF)

Trial Site The trial was carried out on a 2,240 hectare block at the confluence of the Jackson and Arawhata Rivers, near Haast in South Westland. Monitoring conducted before the 1080 application suggested that possum density in the block was moderate-high, and rat density was very low.

This project is also described as a Finding and associated technical report on the ZIP website, zip.org.nz

24

The 1080 toxic bait was applied by GPS-guided helicopter over the entire block on 5 July 2017.

We were fortunate that this application was followed by five fine nights, which maximised the likelihood that all possums and rats in the block would be exposed to the toxin.

A ‘survivor detection area’ of 394 hectares within the centre of the trial area was intensively monitored to assess the performance of the modified technique (assuming it was representative of the entire trial site). The detection area was situated away from the boundaries of the block to maximise the probability that any animals detected were survivors of the operation, rather than animals that had entered the area from outside it.

ABOVE:

Map showing treatment area and monitoring lines (LINDSAY CHAN)

Five days after the toxin was applied, our team lured 964 tracking tunnels with Nutella, and deployed 482 peanut butter-lured chew cards throughout the detection area. All of the devices were checked and refreshed weekly, or whenever river conditions allowed access to the detection area.

The detection devices were monitored for 55 days after the application of the toxin, to maximise the probability of detecting any survivors and, if any survivors were detected, to enable a second application of toxin to be applied before they could breed independent young.

The detection team also recorded observations of non-target species.

Twenty days after the toxin application, 97 motion activated cameras were also deployed throughout the area. The footage recorded was checked weekly.

25

ABOVE:

ZIP field ranger Nate St Hill with a tracking card (DAVE KWANT)

Results The 55-day period that the network of detection devices - i.e. tracking tunnels, chew cards and cameras - was monitored provided 83,410 opportunities to detect possums or rats (i.e. the ‘opportunities’ = the sum of the number of days that each device was monitored for).

Over the 55-day period, no rats or possums were detected.

26

The following non-target species were found dead in the detection area: 1 chaffinch, 1 song thrush, 3 blackbirds, 2 miromiro (tomtits), and 3 red deer. We assume that 1080 caused their deaths, but did not undertake toxin residue testing to confirm this.

The field team recorded 31 instances of seeing or hearing kea within the detection area after the application of the toxin. The motion activated cameras also recorded 6 encounters with kea. In addition, the cameras recorded encounters with 1 kakaruwai (South Island robin), 1 miromiro (tomtit), 1 kākā, 1 song thrush, 8 blackbirds, and 6 red deer.

Conclusion and Next Steps The South Westland trial is possibly the first time that a single aerial application of 1080 has been shown to have successfully removed all of the possums and rats from an area. The possum numbers prior to the aerial application of 1080 were moderate-high and we therefore consider the trial represented a â&#x20AC;&#x2DC;hard testâ&#x20AC;&#x2122; of our modified technique. Although the rat numbers were initially very low, the results were nonetheless pleasing.

A small number of non-target deaths were observed in this trial. However, the non-target animals seen alive on the cameras during the detection period provided strong evidence that the overall impact was very low. While inconclusive, it is particularly encouraging that we did not observe any negative impact on kea during the trial.

The Taranaki and South Westland trials have led us to conclude that the modified technique for applying aerial 1080 shows excellent potential to be able to completely remove possums from large areas of predominantly native forest. We also concluded that the technique shows very good potential to be able to completely remove rats from similar sites.

Following this trial we began to progress a research and development programme in the Perth River valley, South Westland, with the aim of completely, and permanently, removing possums from an area of 12,000 hectares.

Work began at this site in January 2018, and will continue to be a major area of focus through 2018â&#x20AC;&#x201C;19.

BELOW:

Kakaruwai (South Island robin) in Upper Barlow River catchment, Perth River research area (CHAD COTTLE)

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Conservation outcomes in an R&D context – whio and toutouwai success on Taranaki Mounga Radio tracking of some of the birds recorded considerable mobility of whio between waterways, which could account for them not being found during river surveys. This behaviour may also be linked to the river habitats being scoured by floods, and the birds needing to search wider for food. For the first time ever, some individual birds were found to have eaten the cereal baits used in the aerial baiting operation. Importantly, no whio are known to have died from 1080 poisoning (despite close monitoring of the population).

ABOVE:

Whio (BRIAR COOK)

You may recall that our 1080 to Zero trial on Taranaki Mounga last year was hampered by bad weather. Well, it wasn’t just our work that was affected – the native species on the Mounga suffered too, and none more so than whio.

The whio population on Taranaki Mounga are all founded from translocated birds (many raised in captivity), in a first for whio recovery. As such, these birds are monitored closely to ensure their success.

As it turned out, nearly half of them live in the waterways that were part of our 1080 to Zero trial area (while the Mounga-wide aerial operation covered the rest of the local whio range).

Last year was a tough one for those birds. The near-constant rain and flood events that affected our trial decimated the habitat and food supply of the whio.

This in turn led to a poor season where six breeding pairs were not located in any survey that season, and only one duckling successfully fledged – a record poor season for this population.

28

Now for the good news. This past season – the one immediately post-control on the Mounga and our trial – has been a record breaker, with 69 ducklings hatched and 58 of those successfully fledging.

There is no doubt that the aerial control, and our trial, played a key part in providing the relief from predators required for these birds to breed successfully. These numbers will provide a vital boost to this establishing whio population.

And it is not only whio that benefitted from this trial. The 1080 to Zero trial block, with its impressive predator removal result, was used as the founding site for the reintroduction of toutouwai/North Island robin onto the Mounga, after an absence of over 100 years. The Taranaki Mounga Project is now working to suppress predators long term to ensure the survival of these new arrivals, so they too can successfully establish a population just like the whio.

It is great to see our research and development, even at this early stage, already generating tangible benefit for conservation.

Detect and Respond Projects Knowledge/Tool Gap

Project

Results

Can ZIP’s ‘lean detection’ system for possums be enhanced?

Improve trap placement to enhance the effectiveness of the lean detection system

In March 2018, we relocated the four traps, with ramps and bungee cords, in the lean detection system with the lowest catch rate (a total of one possum over 18 months) to more favourable placements – either with greater visibility to approaching possums, or in preferred habitat.

A ‘lean’ network of remote-reporting leghold traps (1 per 50 ha) appears to have prevented possums from re-establishing at Bottle Rock peninsula since October 2016; however some traps appear to contribute little to the system.

Since then, all traps bar one have caught at least one possum, and the system has continued to prevent possums from re-establishing a population at Bottle Rock peninsula.

RIGHT:

Possum interacting with leghold trap at Bottle Rock peninsula (TRAIL CAMERA)

It is unknown how long it takes for a possum to be caught in a lean network of traps (i.e. the ‘lean detection system’).

The longer a possum is ‘free to roam’ within a protected area, the greater the risk that it will encounter another possum, stop roaming and breed.

Assess the speed with which possums are detected/caught by a lean detection system, by observing radio-collared ‘roaming’ possums

Two GPS collared possums were released at Bottle Rock. Unfortunately, the first possum’s GPS collar failed after 9 days. The second possum roamed for 32 days.

Neither possum was caught in the ‘lean detection’ system; however, given the overall performance of the lean detection network we are confident that both would have been caught, had we allowed the trials to run longer.

Further trials will be carried out at Bottle Rock during 2018–19.

The spatial ‘footprint’ of an individual possum in an otherwise possum-free landscape is unknown.

Investigate movement of individual GPS-collared possums in an environment that is otherwise free of possums

Two GPS-collared possums were released at Bottle Rock during 2017–18. The first possum covered an indicative 63ha over 9 days (before the GPS collar failed), and the second covered 89ha over 32 days, before dying of unknown causes. This wide-ranging behaviour lends support to the use of a ‘lean’ system to detect, and remove, invading possums.

GPS failures limited the data we were able to gather from similar releases at the Jackson-Arawhata trial site, but the behaviour we were able to observe suggested both animals were reluctant to cross the Jackson River.

29

Knowledge/Tool Gap

Project

Results

How to efficiently detect a ship rat incursion at landscape scale?

Investigate the dispersal footprint of rats in an area where they have previously been completely removed (the ‘Gen One’ trial)

Ref. Highlight 3 (pp. 32–35)

Investigate the use of a tunnel-architecture trap, with automatic reporting, to quickly and reliably detect individual rats at landscape scale.

Testing indicated that the ‘ZIP200’ prototype trap box lacked the sensitivity required to completely remove rats or stoats from large landscapes.

Investigate the potential of long range, low powered radio (LoRa) remote data transmission

With the assistance of Spark Ventures, we have confirmed LoRa as an appropriate platform technology for remotely communicating with devices spread over large areas.

The range of an individual invading ship rat can be small (<1ha) and would require a very dense network of devices to reliably detect an incursion.

However, the footprint of the first generation of offspring is expected to be much larger and provided they can be removed quickly, could require fewer detection devices.

An automated system for reporting the detection of ship rats.

Rats are highly reproductive and can quickly establish a population. It’s critical to know as soon as possible when a rat is present in an otherwise ‘rat free’ area, so that a prompt response can be initiated.

We need a remote system that can transmit the presence of predators over long distances (to enable timely response to incursions).

Our ultra-high frequency ‘daisy chain’ automated reporting system works well within our barrier lines (one million trap nights to date), where devices are typically spaced less than 20m apart. However, we also need a system that can transmit results where the network of devices to detect and respond to incursions is separated by longer distances.

Can we use wildlife cameras coupled with artificial intelligence software to provide timely detection of stoats?

The best practice deployment of tracking tunnels is not sensitive enough to detect the presence of all stoats. In addition, stoats are so mobile that timely information is needed to initiate a targeted response.

A new trap, the ‘ZIPinn’, is currently under development, with promising initial results during testing.

Our tests have proven that LoRa technology can communicate between devices that are greater than 170m apart, even in the steep and dissected terrain of dense West Coast rainforest (at the Perth River research area).

During 2017–18 we began to develop a hybrid system with a LoRa backbone using our ‘daisy chain’ technique to get into hard to reach terrain and connect the ‘chain’ to the Iridium satellite network.

Investigate the potential of applying artificial intelligence to camera images (or video) to improve the sensitivity and efficiency of stoat detection

During 2017–18 ZIP co-funded a project led by Grant Ryan (Cacophony Project).

Initial ‘machine learning’ algorithms appear promising for the rapid and accurate classification of small mammalian predators, analysing thermal mass, size, shape and distinctive movement as viewed on thermal camera footage.

ZIP is continuing to support the Cacophony Project by making our Lincoln predator behaviour facility available for product testing and development.

In 2018–19 we propose to begin development of a low-powered field-ready artificially intelligent camera for sensitive detection of stoats (and in time, possums), which we can connect to our Iridium satellite/LoRa backbone.

30

Knowledge/Tool Gap

Project

Results

The ability to reliably bio-mark possums and stoats using a single, long-lasting, bio-marker would enhance our ability to effectively and efficiently measure the effectiveness of management activities (e.g. by tracking movement of animals through a ‘barrier’ system).

Develop reliable bio-marking of possums and stoats

Trials at Lincoln indicate that egg mayonnaise laced with rhodamine B bio-marker, delivered via automated lure dispenser, is highly palatable to both possums and stoats.

To enable landscape-scale deployment of the possum ‘lean detection’ and ‘virtual barrier’ systems, a highly effective, production-ready leghold trap platform is required.

Refine and productionise possum leghold trap platform

Trials are ongoing to determine whether it is possible to reliably bio-mark animals using this method, and if so what dosage is required.

ZIP has designed a highly effective and efficient leghold trap platform, which intercepts an estimated 40–60% of possums that attempt to breach the first line in a ‘virtual barrier’ (as tested at Bottle Rock peninsula).

We have contracted Talbot Technologies to manufacture this platform, to enable scaled-up deployment and ensure that these devices can be made available for others to use, from late 2018.

A daytime lock-out mechanism is also being developed to minimise the potential risk to non-target species from leghold traps and enable trap closure during storm events.

Can we improve our detection toolset for confirming the presence/ absence of possums and rats within our field site?

Develop predator detection dog capability within the ZIP team.

Two predator detection dogs are currently undergoing training, including (i) a rat-specific detection dog, and (ii) a possum detection dog. Ongoing training and handling of these dogs will be the responsibility of two members of the Bottle Rock field team, from late 2018.

RIGHT:

Pepper and Baxter, trainee predator detection dogs (MICHAEL TUNNICLIFF)

31

Highlight three UNDERSTANDING THE DISPERSAL FOOTPRINT OF SHIP RATS ABOVE:

Six day old ship rat pups, bred at Lincoln Predator Behaviour Facility (TIM SJOBERG)

Knowledge/Tool Gap If we are to achieve the vision of a Predator Free New Zealand and enable our wildlife to flourish around us, we need to learn how to remove rats from large areas of the mainland, and to efficiently detect re-invaders and remove them as well.

Our early work – releasing individual rats onto Bottle Rock to see where they went – suggested to us that it is unlikely to be feasible in the medium term to efficiently detect a single invading ship rat at a landscape scale, because doing so will require a high density of detection devices, which will be expensive to install and monitor. However, the real concern is when those invading rats produce

32

offspring and re-establish a population within that rat-free area. In saying that, the dispersal ‘footprint’ of the first generation of offspring (i.e. ‘Gen One’) is likely to be much larger than that of an individual rat which should increase our ability to detect it in a cost-effective way (i.e. fewer devices spaced further apart).

But, the size of the Gen One footprint is unknown. We therefore carried out a project to determine the Gen One footprint in an area where rats have previously been completely removed. This trial was carried out under approval from the Lincoln University Animal Ethics Committee, and approval from the Department of Conservation Franz Josef office.

Method Taking advantage of the successful 1080 to Zero trial (where no rats were detected during the 55 day search period post-aerial operation), we conducted this work at the same site at the confluence of the Jackson and Arawhata rivers (in South Westland).

On 30 August, a secure nest box containing a mother rat and her litter of seven 22-day old pups, bred at our Lincoln predator behaviour facility from wild-caught Canterbury rats, were placed within the trial site. The next day the nest box door was opened to allow the mother and seven pups to disperse into the trial site at will.

During the period of captivity at our Lincoln facility, food containing the bio-marker dye rhodamine B was fed to the rat mother and her pups. Rhodamine B makes a persistent stain in growing hair tissue, which is visible under a fluorescence microscope. Trials at the Lincoln facility showed that this marking can persist up to 85 days after last direct access to the bio-marker. Our intention was to use this bio-marker to enable us to positively identify any rat carcass retrieved through the trial as being part of the Gen One litter.

Prior to release of the rats, an array of detection devices was laid out along pre-existing detection lines used for the 1080 to Zero project, covering a total area of 236 hectares, to monitor the movement of the BELOW:

Predator Behaviour Team Lead Tom Agnew analyses rat pup whiskers under fluorescence microscope, Lincoln (CHAD COTTLE)

released rats through time. The nest box/ release site was located centrally within this area. The devices comprised pre-weathered tracking tunnels (Black Trakka) lured with Nutella, chew cards lured with Picâ&#x20AC;&#x2122;s peanut butter, and motion-activated cameras (Browning). Altogether, the initial detection layout equated to a density of 3.8 devices/ha.

We aimed to service (check and refresh) all the detection devices once per week, but in practice a full check of all detection lines took an average of 8.5 days due to weather-related delays.

We also fitted a radio-transmitter to the mother rat prior to her release, and from 1 September to 16 October, we attempted to locate her by radio-tracking to her daytime den site at least once per week, as weather allowed.

TUN200 and T-Rex kill traps were deployed progressively throughout the trial (to remove the juvenile rats before they reached sexual maturity). All rat carcasses recovered from kill traps throughout the trial were retained and sent frozen to our Lincoln facility to be examined for evidence of rhodamine B consumption.

Development of a Gen One dispersal model is ongoing. Preliminary modelling using data from this trial is based on a framework established in rapid eradication assessment modelling.

BELOW:

Rat pup whisker marked with rhodamine B bio-marker, viewed under fluorescence microscope (TOM AGNEW)

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Summary of Gen One juvenile minimum dispersal distances.

Location

Sex

Weight (g)

Age range (days)*

Approx distance from nest (m)

S850

–

88

53-64

128

FF100

M

125

83-86

243

F1400

M

169

86-90

598

AA350

M

166

86-90

675

BB150

M

164

83-94

682

– Carcass too decayed to determine sex * The age range spans the earliest and latest dates that the rat could have been captured.

Results Seven complete ‘services’ of the Gen One detection area were made between 1 September and 20 November 2017, along with an additional 3 partial services.

Ten rats were kill-trapped in T-Rex traps during the trial period. No rats were trapped in any of the four Tun200 traps. 6 of the 10 trapped rats were positive for rhodamine B marking – i.e. the mother rat and five of her seven Gen One pups (which were juveniles when trapped). The other four captured rats were almost certainly invaders into the field site.

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The table above shows the ‘straight line’ distance between the nest box/release site and capture location of the five trapped Gen One juveniles.

The graph on the following page shows a conservative subjective estimate of the cumulative dispersal ‘footprint’ size of the juvenile rats based on the detections recorded and final capture location during the trial.

The footprint was less than 5 hectares until the juveniles were 40 days old, after which the dispersal rate began to increase exponentially.

The footprint was approximately 10 hectares by 50 days age, and 30 hectares by 60 days age.

Discussion The Gen One footprint trial at Jackson-Arawhata trial site resulted in the first confirmed dispersal distances (refer previous table) from â&#x20AC;&#x2DC;nestâ&#x20AC;&#x2122; of juvenile ship rats recorded anywhere in the world, to our knowledge, and is consistent with previous observations from our trials in Taranaki.

The estimated 30 hectare dispersal footprint at around 8.5 weeks (60 days) that we observed at Jackson-Arawhata suggests that the concept of a sparse detection approach designed to detect breeding events holds promise. This scale of area covered by the juvenile rats suggests that

a highly sensitive device spaced perhaps every 10 hectares within the rat free landscape will have a good probability of detecting at least one of the emergent juveniles (before they are able to breed themselves) â&#x20AC;&#x201C; and one detection will be all that is required to alert the need for a management response to remove the Gen One family.

Just what detection network and type of response are required is part of our ongoing research programme. Our initial proposal in the Perth River research site is to establish a detection network that has devices 100m apart on lines that are 700m apart (i.e. to the bush-line).

Gen One Juvenile Ship Rats' Dispersal Footprint conservative subjective estimate 35

Dispersal footprint (hectares)

30

25

20

15

10

5

0 0

10

20

30

40

50

60

70

Ship rat pup age (days)

35

Lure Projects Knowledge/Tool Gap

Project

Results

Can we reduce the requirement to frequently refresh food lures, which is expensive?

Develop and produce an automated food lure dispenser for possums and rats

This novel lure dispenser is now in use at the Perth River research area.

Reducing the labour cost of refreshing food lures would significantly improve the cost-effectiveness of the Remove and Protect Model (and predator control generally).

The dispenser can be programmed to reliably extrude a set volume of liquid or semi-liquid lure at any time frequency required, and can last for up to one year in the field without refreshing (using a 60ml cartridge) – thereby reducing the servicing cost for traps and detection devices by over 90% (in the Remove and Protect model).

In combination with the Iridium satellite/LoRa platform technology, the dispenser could be controlled remotely.

RIGHT:

Automated lure dispenser with bio-marker-laced mayonnaise (BRIAR COOK)

Can we improve visual lures to increase the effectiveness of leg-hold traps?

Investigate other visual lures to attract possums

While a fluorescent 3D ‘pyramid’ continues to show an improved capture rate compared to a standard 9×9cm white coreflute chew card visual lure, further testing at the Bottle Rock field site is still required to build the sample size and increase our confidence in the result.

Continue to investigate the effectiveness of rat bedding material scents

Initial trials indicated that male ship rat bedding material is an attractive ‘social’ lure for rats, either used alone or alongside a food lure (Nutella) for an ‘additive’ effect. Female rat bedding, coupled with a food lure, appears to have a deterrent effect.

Continue to investigate the effectiveness of rat pup noises

While initial pen testing showed an apparent attractiveness of (ultrasonic and audible) juvenile pup sounds, further tests carried out using an ultrasonic electronic speaker found a range of pup sounds to have a mild deterrent effect. A single ‘chirp’ sound appears promising, however not yet at a level that we would take to a scaled-up field trial.

Previous research has shown that white chew cards are a visual lure for possums (when the cards are associated with leg-hold traps).

We do not have a proven ‘social’ lure for rats.

This may be important in rat-free areas where there is abundant food but rats are ‘lonely’.

The combination of juvenile rat bedding and pup sounds (mimicking a rat nest) appears somewhat promising, although not yet at a level that we would trial in the field.

During 2018–19 we propose to begin audio lure trials using prey sounds such as mice, baby birds and weta.

36

ABOVE:

Upper Barlow River catchment, Perth River research area (CHAD COTTLE)

Future Directions Over the next three years, our strategy is to: i. Develop the Remove and Protect model so that it can be applied across extensive areas of native ecosystems; ii. Make tools and techniques easily available for others to use; and iii. Continue to provide advice to support other major predator-free initiatives Where resources permit, we will also continue to develop other tools and techniques that can be applied in rural/urban environments.

A major focus of the next two years will be continuing our programme of work in the Perth River valley, to test and refine the Remove and Protect model for possums, and develop the model for ship rats and stoats, at a site of 12,000 hectares.

We have completed the development and productionising process for three new predator control tools – i.e. the plastic leg-hold platform, LoRa remote reporting daisy-chain

communication platform, and the automated lure dispenser – which means as soon as our large field trials are complete these tools will be made available for others to use. To enable this, we will explore and implement arrangements to manufacture, distribute and sell these tools (at a set price, within the context of ZIP’s status as a charitable entity).

Development work is still ongoing for the ‘ZIPinn’ rat and stoat trap, and the low-height predator fence. If the work results in successful new tools, then we will initiate the productionising process for them, in order to also make them available to others.

Although ZIP was not set up to provide a public information service about possum, rat and stoat control, we are aware that many people are interested in our work, and so we will continue to try to ensure that our findings and other updates are regularly posted on our website. We will also endeavour to share what we have learned with our colleagues at DOC, and with advisors from other organisations, so they can share this new knowledge more widely.

FU TU RE DIRECTIONS

37

Founding Partners and Funders The following organisations have made our work possible by providing funding, guidance and advice.

Founding partners

Funders

During the two-year period from November 2015 to October 2017, the following dairy companies also supported a suite of projects.

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FO U N DI N G PA RTN ER S A N D F U N DE R S

Financial Summary ZIP’s 2017–18 financial statements were prepared by The Business Advisory Group (TBAG) and audited by PWC. We are pleased that a favourable audit was received.

Charities Services – Ngā Ratonga Kaupapa Atawhai will make the full set of financial statements available at charities.govt.nz shortly.

A summary of expenditure in 2017–18 is provided below.

Initial Removal Administration/ Management

15% $697,519.47

11% $524,570.94

26% $1,226,648.30

Detect and Respond

29% $1,436,468.30

Perth River Valley Project

12%

Lures

$595,559.61

5% $242,431.16

Lures

2%

Barriers

$111,452.56

Lincoln Predator Behaviour Facility

Caroline Wallace has, once again, assisted us with efficient book keeping and diligent management of ZIP’s accounts during the year. Thank you, Caroline!

FINA NCIA L SU M M ARY

39

Predator Key Facts Adult Weight

Home range size

Breeding season

Oestrous cycle

Possums

1.4–6.4kg

0.7–3.4ha – male 0.6–2.7ha – female

March – June, occasional Spring breeding

26 days

Ship rats

50–295g

0.3–11.4ha

All year, reduced in winter

4–6 days

Norway rats

103–550g

0.8–21ha

All year, reduced in winter

7–14 days

Stoats

170–450g

80–810ha – male 20–186ha – female

August – December

N/A – 1 per annum

Mice*

12–30g

0.3–2.6ha

All year, reduced in winter

4–6 days

*Mice are outside the scope of the Remove and Protect model ZIP is developing, because:

1. Areas from which possums, rats and stoats have been removed (e.g. fenced sanctuaries such as Zealandia and some offshore islands) have achieved significant biodiversity gains even when mice are present; and

2. Complete removal (as opposed to ongoing suppression) of mice represents a challenge far beyond the removal of our three target species.

Ref: CM King (2006) The Handbook of New Zealand Mammals, Oxford University Press RIGHT:

View of Queen Charlotte Sound from ridgeline of Bottle Rock peninsula field development site (RORY HARNDEN)

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P R E DATO R K E Y FACTS

Gestation

Weaning

Litter size

Time between litters

Age of sexual maturity

17–18 days

170 days

1, rarely 2

1 year, unless rare double breeding

1–2 years

20–22 days

21–28 days

3–10, average 5–8

27–38 days, average 32 days

2–4 months

21–24 days

21–28 days

6–12, average 7

35–49 days, can breed immediately if conditions suit

2–3 months

21–28 days, after a delayed implantation period of c. 280 days

49–84 days

8–10

1 year

3–5 weeks – female 10 months – male

19–21 days

20–23 days

2–9, average 5–7

20–30 days

8 weeks, or the following spring

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ABOVE:

Earina autumnalis (raupeka, or Easter orchid) near Scone Hut, Perth River valley (BRIAR COOK)

Glossary 1080 to Zero

modified approach for aerially applying 1080, developed by ZIP with advice A from DOC, OSPRI and Manaaki Whenua – Landcare Research, to completely remove introduced predators. The approach differs from a ‘standard’ 1080 operation in that the application of toxic bait is preceeded by two non-toxic ‘prefeed’ applications, the toxic sowing rate is 4kg/ha (as opposed to 2kg/ha) and bait is sown in such a way as to ensure full coverage of the treatment area (no exclusion zones, and overlapping baiting swaths).

A24

self-resetting kill trap targeting rats, stoats, weasels and mice, developed by A Goodnature (goodnature.co.nz).

Automated lure dispenser (ALD)

novel lure dispenser designed by ZIP that is capable of holding and A dispensing a fresh food-based liquid or semi-liquid lure in the field every night for up to a year.

Complete removal

he removal from an area of all individuals of a species, or of enough T individuals that the remaining population is no longer viable (i.e. functionally extinct).

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G L O S SA RY

Gen One

The first generation of rat offspring born within a protected area.

Lean detection

sparse network of devices to detect invading possums, rats or stoats in a A protected area, to enable a rapid management response before a population can re-establish.

LoRa

oRa is radio technology that has been developed to enable low data rate L communications to be made over long distances using very low power levels.

OSPRI (Operational Solutions for Primary Industries)

SPRI is a partnership between primary industries and the government, and O manages two national programmes – TBfree and NAIT. The TBfree programme aims to eradicate bovine TB from New Zealand by 2055. NAIT is the national animal identification and tracing system.

Protected area

n area under protection, which has been cleared of possums, rats A and/or stoats.

Pyranine

non-toxic bio-marker that fluoresces bright green under a UV light, and A temporarily stains the digestive tract of animals that have ingested it, along with any areas of skin, fur or feathers that have contacted the marker.

Remove and Protect

he broad approach that ZIP is developing, whereby invasive predators are T completely removed from an area, and that area is then protected against population re-establishment.

Rhodamine B

chemical compound and dye, sometimes used as a bio-marker. Rhodamine A B fluoresces bright pink under a UV light, and temporarily stains the fur and digestive tract of animals that have ingested it. It is also detectable as a glowing ‘band’ in whiskers when observed under a fluorescence microscope.

Snap trap

wooden, metal, or plastic trap with a powerful snap hinge intended to kill A rodents instantly on contact. Snap traps are typically used with some form of bait to lure the rodent to the trap.

TUN200

Z IP’s prototype rat and stoat trap box, which contains two side-by-side DOC200 kill traps in a ‘run-through tunnel’ architecture.

Virtual barrier

n intensive network of lines of traps installed to prevent invasion by A possums, rats and stoats into a protected area.

ZIP200

Z IP’s prototype run-through tunnel/box, which contains a single DOC200 kill trap. Superceded by ZIPinn prototype trap box (see below).

ZIPinn

Z IP’s prototype ‘tunnel’ trap for rats and stoats, which consists of a tunnel with a spring-loaded door (or doors) that closes when a trigger plate is stepped on inside it.

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