We are hiring! Field Team Leader - Twizel

Zero Invasive Predators (ZIP) is seeking an experienced Team Leader to support the culture and development of our tīma (team) in a full time capacity.  

The role is based in Twizel, with opportunities to travel and work in beautiful and remote places of the South Island.

About ZIP

At ZIP, our mission is to protect native taonga and restore te taiao (nature) by removing invasive predators across mainland Aotearoa. ZIP is working to adapt and refine our elimination approaches to completely remove predators within the context of three landscape scale projects: Predator Free South Westland (PFSW), Te Manahuna Aoraki Project and Predator Free Rakiura (PFR). 

The role

You will lead and support a team of 5-10 field rangers both on and off the field, with a primary focus on people leadership and a strong team culture. Through empathetic and effective leadership, you will contribute to the successful delivery of the Te Manahuna Aoraki Project.
You will work closely with the Project Manager, work leads, and the wider ZIP team, in collaboration to maintain high-performing, goal-oriented teams.

Tasks

• Ensuring the team is healthy, happy, engaged and productive. Supporting your team to make sure they understand what is being asked of them by the work leads and how the work relates to our projects.

• Work in the field to remain grounded and connected to the mahi.

• Developing strong relationships with the field team and wider ZIP team. Connecting with leads, and managers for context/support.

• Identifying and supporting development and growth opportunities for the team, including mentoring opportunities, to maximise the potential of your team in both performance and productivity.

• Administration, managing leave, rosters etc

• Being actively involved in field work.

Key Requirements

• Proven experience in supporting a team.

• Clear and empathetic communicator.

• Willingness to learn and adapt priorities at short notice.

• Experience working in an outdoor setting. Experience and understanding of predator control is preferred but not essential.

  Comfortable in a dynamic work environment.

• Physically fit and able to work in some of the Mackenzie’s most challenging terrain.

 ZIP Culture

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

Applications close:            4 weeks or until a suitable candidate is found

Salary: $70,000 - $85,000

Accommodation and food can be supplied as part of your salary package if required.

All applicants must be eligible to work in New Zealand.

We will be accepting applications until midday on Friday 2nd May 2025, or until a suitable candidate is found.

For more information, please email your questions to careers@zip.org.nz, providing your name and a contact phone number with ‘Twizel Team Leader’ in the subject.

Protecting pukunui on Rakiura

The Department of Conservation (DOC) wants to increase predator control to protect native species including pukunui/southern New Zealand dotterel on Rakiura/Stewart Island.

This predator control operation is being led by the DOC team on Rakiura. ZIP has been engaged to help deliver the operation and provide support with community engagement and consultation.

Upcoming drop-in sessions in Oban

Come by to learn more about the proposed operation, why it’s needed, and how potential impacts will be managed. We want to hear your feedback and answer any questions you have.

Thursday 11th April 2025

Two sessions:

• 10am – 4pm

• 7pm – 9pm

St Andrews Anglican Church Hall

110 Excelsior Road, Oban

No bookings required, just come by when it suits you.

You can email pukunui@doc.govt.nz at any time to share your thoughts.

Native wildlife needs protection here

Rakiura is home to a wide array of native birds, reptiles, and bats. Some are not found anywhere else in the country, including the pukunui/southern NZ dotterel, Rakiura tokoeka kiwi, and harlequin gecko.

With its diverse birdlife and wild beauty, it is easy to believe the island is thriving. But many of its natural values are in decline – and the culprit is introduced mammalian predators. Feral cats, possums, and three rat species cover the island, eating birds, eggs and chicks, as well as the fruit, leaves and seeds that nurture the forest ecosystems.

The bush wren and Stewart Island snipe have already been lost forever. The tīeke/saddleback and kākāpō have been evacuated to offshore islands for their survival. The pukunui remains, but it is on the brink of extinction because of predation by feral cats. We must act now using the best tools and methods available to protect pukunui and other native species before it’s too late.

The Pukunui Recovery Project

The Pukunui Recovery Project, run by DOC, has been controlling predators and monitoring the pukunui population since 1994. The last 30 years have been a roller coaster, with periods of population recovery and decline.

Initially, ground-based control of feral cats using 1080 bait proved effective. Pukunui numbers grew from just 62 individuals in 1992 to 290 in 2009. However, despite ongoing control, the population later fell to 126 in 2016.

Additional predator control measures were put in place, including the reduction of other predator species, new trap types and ground-based hunting. Through adaptive management, another period of growth was achieved, with the population recovering to 173 birds by 2020.

Unfortunately, over the past four years there has been a steep decline to just 101 birds. This has prompted the need for an urgent predator control operation using aerially-applied 1080 bait. The Pukunui Recovery Project is aiming to rebuild the pukunui population to at least 300 birds by 2035.

The plan to control introduced predators

The DOC team on Rakiura, in partnership with ZIP, is planning to reduce feral cats across approximately 40,000 hectares of Rakiura National Park. This will cover a variety of terrain in and around the Tin Range, including alpine shrublands where pukunui breed and lower lying kamahi/podocarp forest. The operational boundaries include buffer zones outside of the pukunui breeding area to account for feral cats, as they have large home ranges.

How we will achieve this

The most effective way to control predators over large areas is to use bait pellets containing sodium fluoroacetate (1080). Helicopters distribute the bait across the forest along pre-determined and GPSmonitored flight paths. Possums and rats eat the bait, and feral cats are controlled as they eat the poisoned rats.

This is the only way to control these predators across vast, remote and rugged landscapes. Ground-based trapping and bait stations are effective in smaller, more accessible areas. However, the number of predators can overwhelm trapping networks. The toxin brodifacoum will not be used in this aerial predator control operation.

Proposed timeframe and sequence

The pukunui predator control operation is planned to occur between June and September 2025. It will be carried out in two phases. The exact timing is weather dependent as at least 48 hours of fine weather is required to deliver each application of bait.

The operation begins with the distribution of pre-feed non-toxic bait to prepare predator species to eat the toxic bait that will be applied afterwards.

Phase 1: From June – Two applications of pre-feed non-toxic bait within the smaller eradication trial block, followed by toxic bait. This will be repeated in phase two.

Phase 2: From August – One application of pre-feed non-toxic bait across the entire operational area of approximately 40,000 hectares, followed by one application of toxic bait.

The proposed operational area

The map below shows the proposed area of approximately 40,000 hectares for predator control. It also shows where recreational hunting areas intersect with the operational area. You can see a map of the eradication trial area further down.

Given the scale of the operational area, multiple helicopters will be used to distribute bait. The site where bait will be loaded onto helicopters is yet to be confirmed. It will be away from Oban to minimise any disruption to the community.

Parties that may be directly impacted by the loading site location and helicopter flight lines will be identified and consulted with.

Monitoring predators and pukunui

Rats, feral cats and possums will be monitored in the operational area before and after the operation. We expect to control more than 95% of these predators in the area.

This will provide vital support for pukunui. Other native species will also benefit including Rakiura tokoeka kiwi.

DOC is completing its annual survey of pukunui in March this year. As part of this, juveniles are being banded so their development can be monitored. The survey will be repeated next year.

Operational consent process

The operation requires permission from Te Whatu Ora – Health New Zealand.

Environment Southland is also being engaged to ensure resource consent requirements are met.

DOC has the delegated authority from the Environmental Protection Agency to decide applications for permission to use 1080 on land administered or managed by DOC.

DOC ensures that all legal and policy requirements are met, and that any potential risks of the operation are managed.

Coastal boundaries and marine monitoring

DOC and ZIP are working closely with the commercial fishing and aquaculture industries on Rakiura to ensure the operational plan safeguards these economically vital industries.

Bait will not applied directly into the ocean or outside the operational boundaries. We use the best technology available to accurately distribute bait along predetermined and monitored flight paths.

Water supply management

To maximise the benefits of the operation for pukunui and other native species, no exclusion zones are proposed within the operational area.

The water supply at Rakeahua Hut will be disconnected before toxic bait is distributed, and water will be supplied from another source.

We're engaging with the maritime community to ensure that known creek water sources within the operational area have appropriate precautionary measures in place.

Mitigating impacts on hunters

We are aware of the impacts of aerial operations on recreational hunting, and we are working with the hunting community to understand concerns.

To minimise these impacts, we are proposing to use deer repellent in areas where hunting blocks overlap with the operational area. This will allow us to monitor both the efficacy of repellent on reducing impact on whitetail deer populations and measure the efficacy of repellent bait on target species.

Have your say

DOC and ZIP are consulting with a range of individuals and parties that may be affected by the proposed pukunui predator control operation.

This includes Te Rūnanga o Ngāi Tahu and its respective Papatipu Rūnaka, landowners adjacent to the proposed operational area, the Rakiura Māori Lands Trust, the local aquaculture and fishing industry, Rakiura National Park concessionaries, and commercial operators such as hunting groups and tourism businesses.

If you have been contacted by DOC or ZIP as an affected party for this operation, then we would like to understand how you could be affected.

As part of this consultation process, we will consider what we can do to mitigate any effects. Your feedback during consultation will help guide decisions about the operational plan.

Community meeting in Oban

DOC and ZIP are hosting community meetings to provide people in Rakiura with an opportunity to discuss the operation.

Oban: Tuesday March 25th at11am and 7pm at the Stewart Island Community Centre

Consultation next steps

Once the consultation process is complete, DOC and ZIP will update you about the outcomes of the consultation and any operational changes.

This update will include a notification fact sheet with a more precise timeframe for the operation and the confirmed operational plan and map.

For more information

Contact DOC and ZIP by emailing: pukunui@doc.govt.nz

Predator Free Rakiura

Update on eradication trial

ZIP, on behalf of Predator Free Rakiura, had originally proposed to carry out a predator eradication trial across 10,000 hectares at the southern end of Rakiura during autumn 2025. This trial is now proposed to take place in 2026. It will be informed by ongoing discussions and research throughout 2025.

Additional, smaller-scale trial

While the pukunui recovery operation is a standalone response to an immediate conservation crisis, it also presents an opportunity to gain critical insights into predator behaviour and control methods on Rakiura.

ZIP is designing a small-scale eradication trial to be conducted alongside the pukunui operation, within the proposed operational area.

This trial involves an additional application of non-toxic prefeed and toxic bait, followed by intensive predator detection. This method has been used to successfully eradicate predators from large areas in South Westland and Te Manahuna Aoraki.

This trial will help us to learn about the effectiveness of aerially-applied 1080 to eliminate rats in the Rakiura context, before the eradication gets under way.

Deer repellent research

Predator Free Rakiura is continuing to work through stakeholder interests and concerns around the project.

In response to requests from experienced hunters, ZIP wants to trial the use of deer repellent during the first stage of the eradication. In support of this proposal, work is underway to understand how effective deer repellent is for reducing the impact of 1080 on whitetailed deer, and whether it reduces the effectiveness of the bait on the target rat species.

Manaaki Whenua is leading a trial with field support from ZIP rangers. From March 2025, non-toxic cereal baits containing deer repellent are being applied by hand in front of monitoring cameras, to observe deer interactions.

These and other trials, along with ongoing discussions with the community, will help guide the design of future eradication operations.

We are hiring! Field ranger - Franz Josef

Zero Invasive Predators (ZIP) is seeking a Field Ranger to join our tīma (team) in a full-time capacity.  

The role is based in Franz Josef, with opportunities to travel and work in beautiful and remote places of the South Island.

About ZIP

At ZIP, our mission is to protect native taonga and restore te taiao (nature) by removing invasive predators across mainland Aotearoa.

Zero Invasive Predators Ltd (ZIP) is a not-for-profit organisation established in 2015 by the NEXT Foundation and the Department of Conservation. We’re working to adapt and refine predator elimination approaches to completely remove predators within the context of three landscape scale projects; Predator Free South Westland project, Te Manahuna Aoraki Project and Predator Free Rakiura. Outside of these field sites, we also have a Predator Behaviour Facility based at Lincoln University in Christchurch, and an office in Wellington.

The role

You will be part of a team based in either Franz Josef tasked with delivering and maintaining elimination of predators in these landscapes.

Duties will include but are not limited to:

• Finding and clearing routes, this may involve working and navigating off track.

• Manual labour involving, setting traps, handling toxins, and humanely euthanising wild animals, loading equipment to and from vehicles, including helicopters and using hand and power tools.

• Sharing your observations and collecting high quality data from the field site.

• Crossing rough terrain on foot, carrying a pack of up to 15 kg. You will likely be working alone for up to 8 hours a day, during all seasons, with exposure to wind, rain, sun and snow.

Additional tasks may include evaluating engineering prototypes, modifying predator traps, maintaining field infrastructure, travelling between sites and engaging with local communities to support conservation activities.

CONTRACT: Permanent, full-time

LOCATION: Franz Josef, West Coast

What we need

• Willing and able to spend long hours working alone in rough terrain and challenging conditions.

• Comfortable sharing accommodation with a small team if required, and willing to contribute to cooking and cleaning duties.

• Experience and confidence in engaging with people and groups of various backgrounds.

• Good time management and initiative.

A full job description is available upon request.

All applicants must be eligible to work in New Zealand.

Applications Close: 11th April 2025

Salary range: $48,880 - $68,000, based on experience

Please apply online, or send a cover letter and CV to careers@zip.org.nz, quoting “Field ranger - Oban” in the subject header. We will be accepting applications until midday on 11th April 2025 or until a suitable candidate is found.

For more information, please email your questions to careers@zip.org.nz, providing your name and a contact phone number so we can be in touch.

We are hiring! Field ranger - Oban

Zero Invasive Predators (ZIP) is seeking a Field Ranger to join our tīma (team) in a full-time capacity.  

The role is based in Oban, with opportunities to travel and work in beautiful and remote places of the South Island.

About ZIP

At ZIP, our mission is to protect native taonga and restore te taiao (nature) by removing invasive predators across mainland Aotearoa.

Zero Invasive Predators Ltd (ZIP) is a not-for-profit organisation established in 2015 by the NEXT Foundation and the Department of Conservation. We’re working to adapt and refine predator elimination approaches to completely remove predators within the context of three landscape scale projects; Predator Free South Westland project, Te Manahuna Aoraki Project and Predator Free Rakiura. Outside of these field sites, we also have a Predator Behaviour Facility based at Lincoln University in Christchurch, and an office in Wellington.

The role

You will be part of a team based in Oban, tasked with preparing for operational delivery of predator elimination in this landscape.

Duties will include but are not limited to:

• Finding and clearing routes, this may involve working and navigating off track.

• Manual labour involving installing monitoring cameras, setting traps and loading equipment to and from vehicles, including helicopters and using hand and power tools.

• Sharing your observations and collecting high quality data from the field site.

• Crossing rough terrain on foot, carrying a pack of up to 15 kg. You will likely be working alone for up to 8 hours a day, during all seasons, with exposure to wind, rain, sun and snow.

Additional tasks may include evaluating engineering prototypes, modifying predator traps, maintaining field infrastructure, travelling between sites and engaging with the local community.

CONTRACT: Permanent, full-time

LOCATION: Oban, Stewart Island

What we need

• Willing and able to spend long hours working alone in rough terrain and challenging conditions.

• Comfortable sharing accommodation with a small team if required, and willing to contribute to cooking and cleaning duties.

• Experience and confidence in engaging with people and groups of various backgrounds.

• Good time management and initiative.

A full job description is available upon request.

All applicants must be eligible to work in New Zealand.

Applications Close: 11th April 2025

Salary range: $48,880 - $68,000, based on experience

Please apply online, or send a cover letter and CV to careers@zip.org.nz, quoting “Field ranger - Oban” in the subject header. We will be accepting applications until midday on 11th April 2025 or until a suitable candidate is found.

For more information, please email your questions to careers@zip.org.nz, providing your name and a contact phone number so we can be in touch.

ZIP teams up with Te Manahuna Aoraki Project

From Friday 1 July, the Te Manahuna Aoraki Project Board engaged ZIP to lead the development and implementation components of Te Manahuna Aoraki Project.

This is a significant milestone for all of our team, but especially for our newest members who have joined us from previous roles with our partner, the Department of Conservation (DOC). We are excited to welcome Adriana Theobald, Chloe Underwood, Doug Rands, Jolene O’Connor, Julia Gibson, Simone Smits, Tom Smits, and Geoff ‘Woody’ Woodhouse to ZIP.  

Te Manahuna Aoraki Project is a partnership between mana whenua, the Department of Conservation, NEXT Foundation, Toitū te Whenua Land Information New Zealand, high country landowners, and other philanthropists and government agencies.

The project launched in 2018, with the vision to protect and revitalise the upper Mackenzie Basin and Aoraki Mount Cook National Park so native animals and plants can thrive. The 310,000 hectare project area includes mountain ranges, dryland tussock grasslands, Lake Pūkaki, Lake Takapō/Tekapo and the extensive braided river systems that feed them. The area is home to an extraordinary range of native birds, plants, reptiles and invertebrates – from New Zealand’s rarest wading bird, the kakī, to the endangered robust grasshopper.

This is an exciting time for ZIP, and we are thrilled by the opportunity to take on new skills, experience and pest elimination challenges across this diverse and spectacular landscape.

Over the next year, we will work to expand the alpine predator elimination in the Malte Brun Range, and turn our attention to eliminating other key threats to native species.

Keep an eye out for updates here, and on the Te Manahuna Aoraki Project website, Facebook and Instagram.

Targeted aerial rat responses no worries for native birds in the Perth River Valley

ZIP’s predator elimination model involves removing predators from a specific area and then protecting it from reinvasion. After the elimination operation, we intensely monitor the area and quickly respond to any predator detections using a range of techniques, one of which is the targeted application of aerial 1080 around the detection site.

Native birds in the Perth River Valley are recovering just as well in areas that have had one or more of these localised aerial treatments, when compared to surrounding areas that were only treated during the main elimination operation.

Earlier this year we reported positive signs of bird recovery in the Perth River Valley following our operation to eliminate possums, rats and stoats. In this update, we take a closer look at how this recovery looks in areas of the valley that have received different numbers of toxin applications. This work is part of the Predator Free South Westland project.

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Setting up a trail camera. A MotoLure that dispenses mayonnaise is placed in the camera’s field of view to attract predators. Photo by Chad Cottle.

In 2019 we removed over 99% of predators in the Perth River Valley by applying aerial 1080 bait to all potential habitat in an elimination operation. We always anticipated that some predators might survive the operation or could reinvade the area over time; after all, an elimination approach requires us to protect the conservation gains we make. Our network of 142 lured trail cameras helps us detect these individuals so we can respond quickly to remove them.

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Possums sneaking a snack of mayonnaise are caught in the act by a trail camera.

Usually, our first response to a predator detection is a ground-based operation using bait stations, traps and detection dogs. In some cases, however, the terrain makes this approach impractical and/or a ground-based response is not enough to prevent the emergent predators from spreading. When this happens, we use an aerial treatment of 1080 bait precisely targeted to the localised area where predators have been detected. The confluence of the Perth and Barlow Rivers seems to be particularly prone to reinvasion of rats from across the Barlow River, and has been treated on numerous occasions over the past three years (shaded dark grey in the map below).

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Perth River Valley predator elimination project area. Grey shading shows the frequency of localised aerial treatments since 2019. Each dot represents a trail camera set up in front of a lure dispenser.

We sometimes get asked if this use of localised aerial treatments is slowing the recovery of native birds present in the Perth River Valley site. There is plenty of scientific evidence that native bird populations do better when predators are controlled (see references, below). Here, we investigated our camera network to see if there was any difference in native bird recovery between areas that had been treated multiple times and areas that only received the initial elimination treatment. Although trail cameras are primarily used to detect predators, they also detect native birds that happen to pass by. When we compare the proportion of cameras that detect birds, at the same sites, over time, we can get an indication of the relative size of these populations.

We looked at three species— kea, kakaruai/South Island robin, and ngirungiru/South Island tomtit. These species are known to be vulnerable to predation and we therefore expect their populations to recover when predators are removed. They are also the species that spend a lot of time on the forest floor and, because the cameras are low to the ground, are detected most consistently. We know that detections fluctuate over the year, peaking in summer with new fledglings. By comparing two late summer months, these seasonal variations are minimised.

We compared the number of cameras that detected birds in January 2020 (one month before any localised treatments took place) with February 2022 (one month after the most recent treatment for which we have analysed data) in areas that had received either none, between one and two, and three or more localised treatments.

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Trail camera detections in January 2020 and February 2022 of kea, kakaruai/South Island robin, and ngirungiru /South Island tomtit in areas of the Perth River Valley that have received different numbers of aerial treatments. Numbers of cameras in each area ranged: 0 treatments, n=25; 1-2 treatments, n=54; and 3+ treatments, n=42

In areas that have received localised aerial treatments, more cameras are detecting kea and ngirungiru than two years ago. Kakaruai detections have remained reasonably stable, which is not surprising given the relatively low number of detections. The very low numbers (or lack) of species detections in areas that have not been treated beyond the initial elimination operation was surprising. However, this result may be explained in part by the habitat type most of these cameras were in (higher altitude in some cases, and the narrow, colder Upper Perth River Valley) where we would expect to find fewer native birds. Across the whole Valley, predator numbers are close to zero, so predation is unlikely to be a factor.

These camera detection results support the increase in birdlife that our field team are seeing and experiencing first-hand. Native bird populations continue to recover in the Perth River Valley, and the localised treatments to maintain predator freedom are not hindering that recovery.

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A pair of kea show off in front of a lured trail camera, June 2022

Acknowledgements

Thank you to Matt Hickson of the Department of Conservation for a review of an earlier draft of this update.

References

Kemp, J. R., Mosen, C. C., Elliott, G. P., & Hunter, C. M. (2018). Effects of the aerial application of 1080 to control pest mammals on kea reproductive success. New Zealand Journal of Ecology, 42(2), 158–168.

Miskelly, C. M., Greene, T.  C., McMurtrie, P. G., Morrison, K., Taylor, G. A., Tennyson, A. J. D., & Thomas, B. W. (2021). Species turnover in forest bird communities on Fiordland islands following predator eradications. New Zealand Journal of Ecology, 45(2), 1–15.

Schadewinkel, R. B., Senior, A. M., Wilson, D. J., & Jamieson, I. G. (2014). Effects on South Island robins (Petroica australis) from pest control using aerially applied 1080 poison. New Zealand Journal of Ecology, 315–321.

van Heezik, Y., Ray, S. M., Jamieson, I. G., Allen, O., & Schadewinkel, R. (2020). Impacts of aerial 1080 predator control on nest success and adult survival of South Island robins. New Zealand Journal of Ecology, 44(2), 1–11.

ZIP accommodation no match for kea in Predator Free South Westland back-country

On Thursday 28 April, ZIP field rangers returned to their tent in the Perth River Valley to find that kea had reduced it to shreds. The Perth River Valley is a remote and rugged 12,000 hectare site within the footprint of the Predator Free South Westland project area. ZIP has been working to eliminate possums, rats and stoats from the site since 2018, and the area is now effectively predator-free.

The large tent, located at the confluence of the Perth and Barlow Rivers and affectionately referred to by the team as the ‘Content’, has been a permanent fixture in the Perth River Valley field site since late 2020. While the field team have enjoyed frequent encounters with kea at the Content, this was the first encounter in which kea in this part of the field site had lived up to their reputation for mischief and destruction – and they certainly made up for lost time!

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During the weekend of Saturday 30 April, the team returned to remove the damaged tent, and found a mob of eight unbanded juvenile kea on, and around, it. As gear was removed from the tent, the birds amused themselves by climbing over the neatly stacked equipment, undoing packages and opening boxes.

The tent, wooden base and all, was removed from the site and returned to the ZIP field base in Franz Josef, where it will undergo some sorely-needed repairs and maintenance. Fortunately for the team, the tent fly appears to have sustained most of the damage, so with the purchase of a new fly the Content should live to fight another day – perhaps at another location within the Predator Free South Westland project area.

ZIP Chief Executive Al Bramley says, “While certainly inconvenient for our rangers, this encounter is another positive sign that kea in the area are continuing to do very well in the absence of possums, rats and stoats. The team is thrilled to be seeing the results of our work with Predator Free South Westland to protect these charismatic, cheeky birds, and we look forward to seeing what hijinks they get up to next!”

South Ōkārito Forest set to thrive

Predator Free South Westland has now completed the second phase of a predator elimination operation in South Ōkārito Forest. This is a major milestone for the project, which seeks to protect and restore nature by eliminating possums, rats and stoats from 100,000 hectares across South Westland. Now, the work to protect the forest against predator re-establishment begins.

Predator Free South Westland Board Chair Katie Milne says, “The elimination of invasive predators from the forest of South Ōkārito will have significant benefits for the last remaining population of New Zealand’s rarest kiwi, the rowi, along with the many other native taonga that call this area home.”

The first phase of the operation was completed in November 2021, and achieved a substantial reduction of possums, rats and stoats. However, a small number of rats survived, and went on to breed in the site. To remove this emerging population, the second phase was initiated on 23 March.

Due to the nature of the South Ōkārito site, this predator elimination operation was particularly complex, and required a combination of aerial broadcast, ‘trickle sowing’, hand- and drone-laying techniques to complete. This complexity was further compounded by a highly unusual turn of events for the West Coast: low rainfall! To ensure that target predators interact with the toxic baits, it is important that no non-toxic prefeed baits remain in the environment when toxin is applied. In South Westland, this would typically occur within 1-2 weeks. In this instance, the prefeed application was followed by 23 fine nights before sufficient rainfall occurred to degrade the bait. Toxic bait was applied between 10-13 April.

The operation appears to have been a success. Pleasingly, no rats have been detected since the operation. If any rats are detected in the coming weeks, they will be removed using targeted ground-based techniques.

A small number of stoats, and an estimated two possums, have been detected in the site since the operation was completed. The team is now working to remove these using targeted ground-based techniques before they are able to re-establish a population.

The measures taken to minimise the risk of karoro (black-backed gulls) eating bait appear to have also been largely successful, and substantially reduced the impact on the karoro population. Pleasingly, there have been no reports of affected dogs or livestock.

The field team has been pleased to report many kea sightings since the operation, and surveys of popular kea sites are also encouraging. A group of kea (including this season’s fledglings) were recently seen at the Pakihi Walk carpark, and local helicopter pilot Gus Gordon reported seeing a flock of kea over the Waiho Loop.

ZIP Operations Director Duncan Kay, who oversees the predator elimination work on the ground, says, “The Predator Free South Westland team has greatly appreciated the ongoing support and patience of the local community during our work to eliminate invasive predators from South Ōkārito. We are now looking forward to protecting the site and watching the native taonga respond!”

Native Birds Continue to Recover in the Perth River Valley

In December 2020 we reported that the number of native birds in the Perth River Valley was beginning to recover due to the removal of predators over the previous 20 months.  This work is part of the Predator Free South Westland project.

Since then, we have continued to see positive signs of native bird recovery.  An insight into their recovery is enabled by the network of 142 lured trail cameras in the Perth River Valley that are deployed to detect possums (Trichosurus vulpecula), ship rats (Rattus rattus) and stoats (Mustela erminea).  We retrieve the data from each camera every 4 to 6 weeks, and then plot and analyse it.  In the almost 3 years that the cameras have been out we have amassed over 2.5 million images!

Each blue dot shows the location of a trail camera in the Perth River Valley. Each camera is set up in front of lure.

A rat investigates a MotoLure (an automated lure dispenser), March 2021

The predator detection data provides vital information about the number and extent of predators, which helps us to plan how to respond in order to eliminate them.  The camera network also regularly detects native birds. These incidental detections also provide a useful indication of how well native species are responding in the absence of predators.

In October 2020 we analysed almost two years’ worth of native bird detections from this network. In January 2022, just over a year later, we once again analysed the proportion of cameras that detected native birds per month, over time.

Please note, the detection network is set up to detect our target species/predators, not native birds. The native birds detected are incidental, and are mainly species that spend time or feed on the ground. Species that naturally occur at low densities, or are primarily arboreal or waterfowl are less likely to encounter one of the cameras.

Incidental detections can provide an indication of the status of native birds in the valley; which for many species, reflects how their populations are responding in the absence of predators. In this update we focus on three species that are regularly detected across the network, from the valley floor to the alpine tops. These species are kea (Nestor notablis), kakaruai/South Island robin (Petroica australis australis), and ngirungiru /South Island tomtit (Petroica macrocephala). The detection rates per month for these species are shown on the following trend graph.

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Detections across the Perth River valley trail camera network of kea, kakaruai and ngirungiru from March 2019 - January 2022

We assume that regularly recorded native species detections also reflect their population trends (just as we do for the predator population trends we analyse from trail camera data).

Some common features of the detection data for of the three species are:

• The number of detections fluctuate over each year, peaking in summer with new fledglings, and dipping in winter/spring as the birds are nesting

• For all three species, detection rates in the month of March have at least doubled between before we undertook predator removal in 2019 and two years later in 2021.  

 Kea

A kea caught on trail camera, October 2021

The local kea population in the Perth River Valley has benefited from previous predator management programmes and local kea experts estimated there were between 75-100 birds in the Valley before we started working there.

The effects of predation on kea and their nesting success are well researched. We know that when predators are managed with well-timed aerial 1080, more than 70% of kea nests are successful with at least one chick surviving.  Without intervention only 40% of nests succeed and this drops to less than 10% of nests when there is a stoat plague (Kemp et al., 2018).

Kea detection rates fluctuate with the seasons, with higher activity in forests (where most of the trail cameras are) over winter, and above the treeline over summer. Despite that, kea detection rates are generally trending upwards.

Detections of kea increased from 8% in March 2019 (i.e. before predator removal began) to 15% in March 2021.

Some of the fluctuation in kea detections could also be due to a bumper breeding season in 2019, after which the fledglings then dispersed to other parts of the backcountry. To put it more technically, there was a “double-clutch” event in 2019 (i.e.  kea nested twice, resulting in a higher-than-normal number of chicks), with the result that the local population appeared to increase substantially. That summer (i.e. 2019/20), our field rangers noted seeing fledglings of two different sizes in the Perth River valley. And then, in early 2021, a team monitoring and banding kea noticed a high number of juvenile kea in the adjacent Whataroa-Butler valley. It is possible that this valley may now be home to many of the birds that originally began their lives in the Perth River Valley.

Kakaruai/South Island robin

Kakaruai/South Island robin are sensitive to predation (Schadewinkel et al., 2014).  Research has shown the nesting success of these at-risk birds significantly improves in the absence of predators, and we should be able to start seeing a difference 1-3 years after a predator operation (van Heezik et al., 2020). 

Detections of robins increased from 5% in March 2019 (before predator removal began) to 11% in March 2021.

A kakaruai in front of a lure, May 2021

Ngirungiru /South Island tomtit 

Of the three species we’ve focused on for this update the ngirungiru has had the most dramatic upward trend in detections.

Even taking into account seasonal fluctuations, ngirungiru have had an increase in detections-from 22% of the camera network in March 2019 (before predator removal began) to 55% in March 2021.

A ngirungiru, September 2021

However, over time we actually may see fewer ngirungiru due to competition with other native species. Recent research suggests that as the numbers of kakaruai grow, they may begin to displace the ngirungiru, and we may see a natural reduction in their numbers (Miskelly et al., 2021).

Other Native Birds

Yellow-crowned kākāriki continue to be regularly seen and heard, and are even beginning to feed on the ground in front of some of the cameras.

A kākāriki beside a MotoLure, June 2021, and a pair of kākāriki recorded August 2021

It’s particularly exciting to be seeing and hearing kākāriki, as their presence is often a good natural indicator of the overall health of a forest or ecosystem (McLennan, 2017).

In August 2019, we began sighting kākā in the Perth River Valley. While we have had more regular kākā sightings from the field team over time, camera detections have been sporadic; most likely due to their slow breeding cycle (Powlesland et al., 2009), and apparently low numbers pre-operation.

Kererū (Hemiphaga novaeseelandiae) continue to pop up in camera detections; although this is sporadic as they don’t often forage on the ground. We previously reported seeing flocks of up to 30 kererū in the skies—field team members have now even seen flocks of up to 80 birds! 

A kererū on the sunny forest floor by a MotoLure, February 2021

Whio do not often show up on our detection cameras because very few cameras are located alongside waterways, which are the natural habitat of whio.  That’s to prevent cameras from being washed away in floods. We have, however, continued to see adults and chicks each year in the Perth River Valley.

We also reported on several other native bird species in December 2020, which the field team continue to see and hear; e.g. korimako/bellbird (Anthornis melanura), tauhou/silvereye (Zosterops lateralis), kārearea /New Zealand falcon (Falco novaeseelandiae), ruru/morepork (Ninox novaeseelandiae), and seemingly endless tūī (Prosthemadera novaeseelandiae).

These incidental and anecdotal detections are a very good indicator that native birds in the Perth River Valley are continuing to recover and that predator freedom has had a positive effect on their populations.

“The bird life on my recent trip into the backcountry was certainly some of the best I have experienced, particularly in the Perth valley from Nolans hut. It’s up there with what I saw on the southern end of Rakiura, and in the Landsborough valley. We spotted a couple of groups of kea, but most noticeable was the kereru; lots and lots of them! Congratulations and keep up the good work.”

— Mark Winter, CFO, My Food Bag (and very keen tramper) – February 2022

Acknowledgements

Thank you to Matt Hickson of the Department of Conservation for a review of an earlier draft of this update.

References

Kemp, J. R., Mosen, C. C., Elliott, G. P., & Hunter, C. M. (2018). Effects of the aerial application of 1080 to control pest mammals on kea reproductive success. New Zealand Journal of Ecology, 42(2), 158–168.

McLennan, J. (2017). The Cape to City Programme: baseline bird counts in treatment and non-treatment areas. A Report Prepared by John A McLennan Environmental Services Ltd, Havelock North, for the Cape to City Governance Group.

Miskelly, C. M., Greene, T. C., McMurtrie, P. G., Morrison, K., Taylor, G. A., Tennyson, A. J. D., & Thomas, B. W. (2021). Species turnover in forest bird communities on Fiordland islands following predator eradications. New Zealand Journal of Ecology, 45(2), 1–15.

Powlesland, R. G., Greene, T. C., Dilks, P. J., Moorhouse, R. J., Moran, L. R., Taylor, G., Jones, A., Wills, D. E., August, C. K., & August, A. C. L. (2009). Breeding biology of the New Zealand kaka (Nestor meridionalis)(Psittacidae, Nestorinae). Notornis, 56, 11–33.

Schadewinkel, R. B., Senior, A. M., Wilson, D. J., & Jamieson, I. G. (2014). Effects on South Island robins (Petroica australis) from pest control using aerially applied 1080 poison. New Zealand Journal of Ecology, 315–321.

van Heezik, Y., Ray, S. M., Jamieson, I. G., Allen, O., & Schadewinkel, R. (2020). Impacts of aerial 1080 predator control on nest success and adult survival of South Island robins. New Zealand Journal of Ecology, 44(2), 1–11.

ZIP Media Release

MEDIA RELEASE: Loss of black-backed gulls and dog during predator elimination.

418 karoro (black-backed gulls) have died as the result of consuming poison bait used in an  operation to remove possums, rats and stoats from a 15,000 hectare block in South Westland. While  the number of dead birds is high, it does appear to be localised to the Waiau (Waiho) River and  nearby coast.  

In addition, a dead dog has also been found, which is likely to have either consumed bait or  scavenged a carcass.  

Al Bramley, ZIP’s Chief Executive, said “The ZIP team is saddened by the unfortunate deaths of these  birds. We are striving to protect the native wildlife in this area and so the team is taking this result  hard. We also acknowledge the upset that this incident has caused for mana whenua Te Rūnanga o  Makaawhio.” 

The predator removal operation, which used sodium fluoroacetate (1080) bait, was carried out by  Zero Invasive Predators (ZIP), as part of the Predator Free South Westland project. This project aims  to restore nature and sustain community by eliminating possums, rats and stoats over a 100,000 hectare area.  

Karoro are not a threatened species, as they are one of the most abundant and familiar large native  birds in New Zealand, with a national population now in excess of one million birds. They are natural  scavengers, and sometimes a pest species on river systems, because they eat the eggs and chicks of  other ground-nesting native birds. They are not given any level of protection under the Wildlife Act.  

At the request of ZIP, a local resident yesterday surveyed the shores of nearby Ōkārito Lagoon, and  reported no issues, and that the usual suite of bird species were present, with no dead birds. 

Native bird populations such as rowi (Ōkārito kiwi), kōtuku (white heron) and kea are expected to  thrive from the removal of possums, rats and stoats. Eliminating possums also removes the risk of  bovine TB for the local farmers. When these predators are eliminated, there will be no need for the  future repeated use of toxins at the landscape scale. This project is also helping to maintain  employment for local people, in a region that has suffered significant loss of tourism due to COVID 19. 

ZIP rangers will continue to survey the beach and other parts of the area covered by the predator  removal operation. Forecast heavy rain this weekend is expected to render the baits non-toxic, but  any predator or bird carcases will remain a risk to dogs until fully decomposed.  

Phase 1 predator elimination operation being completed in the South Ōkārito block

Phase 1 of the predator elimination mahi in South Ōkārito is being completed this week! We expect to begin the aerial application of cereal bait containing sodium fluoroacetate (1080) today (23 November 2021). The baiting should be concluded by the end of 24 November.

As was the case with the non-toxic prefeed applications earlier this month, this operation will involve:

• Closing the Forks-Ōkārito Road between 9am and 2pm (on 24 November) while helicopters are operating overhead and road crews safely undertake post-sowing inspections. There will be no vehicle or pedestrian traffic permitted along the road during this time.

• Closing all DOC tracks within the operational area, as well as beach access south of Ōkārito village. These will remain closed for the full duration of this aerial operation, and ZIP staff will be stationed on site and will advise when these facilities are re-opened.

• Continuing the use of a drone to apply bait, under the watchful eye of a pilot and tracked with GPS, to see how this technology can be used to eliminate predators. Helicopters, using GPS guidance systems, are still doing the majority of the baiting.

 If you are in the South Ōkārito area, please take note of all warning signs and follow the guidance provided. This advice is there to keep you, your whanau, and your animals safe. Please do not touch any bait if you come across it.

 Dogs should be kept under strict control at all times and have no access to the operational area, as they are highly susceptible to poisoning. The beaches and river banks are a high-risk area for dogs following aerial 1080 operations. Please note that poisoned carcasses may be present in the area for some months after the completion of this work, and these present a risk to dogs.  

 With regards to hunting, information on where bait was applied and the associated hunting cautions can be found on the DOC Pesticides Summary page (https://www.doc.govt.nz/nature/pests-and-threats/pesticide-summaries/). 

 Your support for this important mahi is very much appreciated – we acknowledge that these temporary restrictions may cause some inconvenience. Thank you for doing your part to help make South Westland predator free.

 This predator elimination mahi is part of the Predator Free South Westland project, which aims to eliminate predators from 100,000ha of South Westland. Removing predators from South Ōkārito will enable rowi, kōtuku, kea and other taonga to thrive. Eliminating possums also removes the risk of bovine TB for the local farmers. Without these predators around, there will be no need for repeated landscape use of toxins. Furthermore, this project is creating jobs, and maintaining employment, for many in the local region that has suffered economic hardship from the significant loss of tourism.

Phase 1 of predator elimination work is continuing in the South Ōkārito block

Phase 1 of the South Ōkārito aerial operation continues this week, with the second of two non-toxic prefeed applications taking place on Thursday 18 November. Using non-toxic prefeed bait gives predators a taste for the pellets, which they learn to treat as a food source – increasing their uptake of the toxin bait that is subsequently presented to them.

The toxin application – the final step of Phase 1 – will take place no sooner than 22 November.

There will be no aerial operations over the festive holiday period. Phase 2 is expected to begin in late January.

Just like the earlier prefeed application completed on 3 and 4 November, the second prefeed will involve:

• Closing the Forks-Ōkārito Road between 10am and 2pm while helicopters are operating overhead and road crews safely undertake post-sowing inspections.

• Closing all DOC tracks within the operational area, as well as beach access south of Ōkārito village. ZIP staff will be stationed on site and will advise when these facilities are re-opened.

• Continuing the trial use of a drone to precisely sow bait along the boundary edge of the operational area. The drone is being deployed, under the watchful eye of a pilot and tracked with GPS, to see how this technology can be used to eliminate predators. Helicopters, using GPS guidance systems, are still doing the majority of the sowing

• Using non-toxic prefeed bait that is dyed green. This is to support the work done to train kea to avoid eating cereal bait (they have already learnt to avoid look-a-like baits because those ones temporarily make them feel sick).  

 In conjunction with the aerial operations, ZIP have now begun baiting some of the ground-based predator elimination devices that are around the perimeter of the block. Combining aerial and ground-based operations, along with cutting edge technology, gives the best chance of success for the Predator Free South Westland project.

Removing predators from South Ōkārito, and throughout the PFSW project area, will enable rowi, kōtuku, kea and other taonga to thrive. Eliminating possums also removes the risk of bovine TB for the local farmers. Without these predators around, there will be no need for repeated landscape use of toxins. Furthermore, this project is creating jobs, and maintaining employment, for many in the local region that has suffered economic hardship from the significant loss of tourism.

Your support for this important mahi is very much appreciated – we acknowledge that there may be some inconvenience along the way. Thank you for doing your part to help make South Westland predator free.

Sniffing out rats on both sides of the Tasman

ZIP Field Ranger Chelsea, and Rat Detection Dog Baxter’s job is to find rats that have either survived a predator elimination operation, or that have reinvaded an area that was previously predator free. They usually spend their days trying to find rats within the footprint of the Predator Free South Westland project. They got more than they bargained for earlier this year though, when they left the West Coast and ventured off shore to help with a rat invasion.

Chelsea and Baxter (taken before their adventure abroad)

Lord Howe Island is some 600km off the coast of New South Wales, and is home to many unique and special species. The island had been rodent free for 16 months. So, when a rat incursion occurred, Chelsea and Baxter, along with another team from the NZ Conservation Dog Programme, headed over to help.

The settlement area of Lord Howe Island

Due to the Delta outbreak, getting home was much more complicated than getting over to Lord Howe. What was supposed to be a short stint turned out to be a lot longer. While a tropical island is not a bad place to be stranded, they were keen to get back to Aotearoa. Their return home was further complicated by having to leave the dogs behind, and wait to be reunited once the dogs had passed a health check. You can read more about their mahi on the island and their mission to get home in this Stuff article.

Aside from the hitches in getting back and being separated from loved ones, Chelsea said that it was a great experience overall. She enjoyed being part of a squad of dog teams, and the different setting gave her valuable insight into their work back home – the challenging but rewarding task of detecting the last few rats in South Westland terrain.

One of Chelsea’s key observations was it seemed easier to pick up on the rats on Lord Howe Island. She puts this down to the rats being used to living around humans, and making their nests on the ground where Baxter could find them more readily. The warm weather also preserved scent for longer, compared to the wet West Coast.

Chelsea and Baxter detecting rats on Lord Howe Island

Having the experience of working in a residential setting (most of the Lord Howe Island work was within the main settlement) was also really valuable for Chelsea and Baxter. ZIP has just begun predator elimination work in and around South Ōkārito, which includes some private land and settlements.  Chelsea gained an insight into how important it is to engage with the community, and found the experience enriching, albeit challenging at times.

For Baxter, the highlights were endless. He got to have the excitement of regularly finding recent rat scent, and because his reward for finding rats is playing with his favourite ball, he was pretty chuffed to be searching around residential properties. Aside from the retrieval of rat carcasses, Baxter’s side hustle was retrieving lost tennis balls in backyards – his best tally was six in one day!

Predator elimination work underway in South Ōkārito for the Predator Free South Westland Project

Over the past 9 months, on behalf of Predator Free South Westland, ZIP has been preparing to remove predators from the South Ōkārito block. Much of this planning has involved numerous conversations with Makaawhio, the local community, and private landowners. These conversations have been instrumental in guiding what this work will look like.

To begin the predator elimination mahi, ZIP are now getting underway with the aerial operation. The first non-toxic prefeed application is taking place on Wednesday 3 November. Toxin will not be applied until after 15 November.

The non-toxic prefeed bait is dyed green. The reason for this is that, over the past several months, ZIP have been teaching kea to avoid eating cereal bait by providing them with look-a-like baits that temporarily make them feel sick. Doing this makes kea much less likely to eat toxic bait when they come across it later.  

During the baiting operation, the Forks-Ōkārito Road will be closed (for up to 4 hours) while helicopters are operating overhead and road crews safely undertake post sowing inspections. All DOC tracks within the operational area, and beach access south of Ōkārito village will also be closed during the pre-feed operation. ZIP staff will be stationed on site and will advise when these facilities are re-opened. We acknowledge these disruptions may cause inconvenience, and thank you for your understanding and support for this important work.  

ZIP are also gearing up to start the ground-based predator elimination around the perimeter of the rowi sanctuary, with good progress being made on installing bait stations and traps. The team will begin applying the bait and setting those traps within the next few weeks.

Removing predators from South Ōkārito, and throughout the PFSW project area, will enable rowi, kōtuku, kea and other taonga to thrive. Eliminating possums also removes the risk of bovine TB for the local farmers. This project is creating jobs, and maintaining employment, for many in the local region that has suffered economic hardship from the significant loss of tourism.

From the trap to the (autopsy) table

As part of a recent current affairs episode looking at the PF2050 mission, a film crew from Australia showcased a part of our work that doesn’t often get airtime – what happens to a rat after it has come to its demise in one of our traps?

While a capture might seem like the natural end point – there is actually a lot more to the story.

ZIP is currently field trialling a highly effective trap that humanely euthanises the rat once caught, allowing the retrieval of an intact body. Once the trap has been sprung, a node on top of the trap pings out an alert to the rangers to go and check it out. As you can see in the video the rat carcass gets safely stowed away in a snaplock bag (or perhaps a retired lunch box) ready for its journey over the main divide to ZIP’s research facility at Lincoln.  

Once in the lab the rat carcass undergoes a forensic autopsy. This might sound like something out of a crime show, but the information a single rat can tell us is huge.

From its teeth we can tell how old it is. The whiskers can tell us where the rat came from – if the whiskers glow under fluorescence microscope, then it is an invader who ate a biomarked snack we left for it along the way. And if the rat is a female, we can tell if it has bred and how many times it has produced young – we will know if it was just a solitary rat or if there are another eight or more still to be caught out there.

All the information we’re able to glean from these dead rats help us to unpick the challenge in front of us – and is vital to driving the innovation we need to get to a predator-free Aotearoa by 2050.

You can watch the video either through the embedded viewer on this page or here on Al Jazeera English’s YouTube page. The story features other conservation initiatives, with the main section about ZIP’s mahi starting in just before the 17min mark.

Predator elimination work underway in the Whataroa-Butler catchment area

Seven juvenile kea spotted together in the Perth River Valley, April 2020. Image © ZIP Ltd.

We have begun the programme of work to eliminate predators from the Whataroa-Butler catchment area – using the same approach that ZIP successfully used in the neighbouring Perth River valley in 2019. This is the first step towards achieving a Predator Free South Westland.              

Just after Easter, we undertook the first of two (planned) non-toxic aerial prefeed baiting applications. The non-toxic prefeed bait is dyed green. This is to make sure it looks identical to the bait we are using to teach kea to avoid bait the next time they come across it.

The toxin application (using bait that has also been dyed green) is expected to be completed by mid June, weather pending.

We will not be preventing public access to the area while we are working there. Prior to toxic baiting, warning signs will be placed at each hut. Water supplies will be temporarily disconnected until the bait is cleared from the immediate surrounds. Toxic bait will also be cleared from public tracks immediately after sowing.

Predator Free South Westland

On the 11th of March the Minister of Conservation, the Hon Kiritapu Allan, officially launched Predator Free South Westland (PFSW). 

Eliminating possums, rats and stoats from 100,000 hectares of South Westland is an ambitious goal. We are excited to play our part in PFSW. ZIP will be responsible for the day-to-day operational delivery of the project. This is the first time as an organisation that we will be playing dual roles of being the ’boots on the ground’, while also researching and developing novel ways to eliminate predators.

No-one has ever attempted to completely remove possums, rats and stoats from such a large area of the New Zealand mainland, let alone across such diverse landscape types, from the mountains to the sea.  We expect there to be challenges along the way. We might even need to go back to the drawing board to further refine our methods. There will also be circumstances, like Covid-19 and extreme weather, that may slow us down.  But this mahi is worth doing — eliminating predators will allow the unique and special species that live in the area to thrive.  And, by using our remove and protect approach, once free of predators, there will be no need for large-scale repeated use of aerial toxin in the project area.

PFSW is a massive investment in the future of South Westland. The impact from Covid-19 has had a devastating effect on the livelihoods of people in South Westland. This project won’t just benefit nature — it will also bring social and economic benefits to the region.  ZIP has been based on the West Coast for several years now. Basing ourselves in South Westland not only makes sense in terms of doing our work, but it also embeds us within the local community.

For more information about the project, please visit Predator Free South Westland's website.

Great news: Native birds are beginning to recover in the Perth River valley!

We are delighted to report that native birds have begun to recover in the Perth River valley, just 18 months after our winter 2019 predator removal operation successfully eliminated stoats. In July, follow up actions removed the last resident possum, and we have now almost finished off the last few rats.

We recently analysed almost two years’ worth of native bird detections from our network of 142 lured trail cameras. In the graphs below, these detections are broken down by the percentage of the camera network that detected each species every seven days.

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Note:

1. There are currently two gaps in the data, on November 1-21 and April 14-28, in which footage has not yet been processed. We will update the graphs as soon as this footage review is complete.

2. The camera network has also infrequently detected ruru (morepork) throughout the survey period.

The lured camera network is low to the ground, and is designed to detect possums, rats and stoats, not native birds. Therefore, these incidental records are unlikely to show the full extent of recovery as a result of the predator elimination. Nevertheless, this network has provided us with rich data about the activity and relative abundance of a wide range of species within the Perth River valley—demonstrating once again the versatility and value of this camera tool.

Highlights

Kea

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Juvenile kea in the Perth River valley, March 2020 (Chad Cottle)

The Kea Conservation Trust (KCT) and DOC have reported that kea up and down the West Coast double-clutched (mated and raised fledglings twice) during the 2019-20 breeding season.

Our observations in the Perth River valley support this conclusion. Fledgling kea were spotted in the site as early as October 2019, and as late as March 2020, and young kea in different age classes have been seen within the same period. This indicates that kea have had a very successful breeding season, which is likely to be significantly enhanced by the absence of stoats in the valley.

Both ZIP team members and experienced helicopter pilots continue to report frequent kea sightings during their work in the field site, including a memorable encounter with 13 juvenile kea in February 2020, and another with 27 juvenile kea in April 2020.

Kākā

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A juvenile kākā caught on camera in the Perth River valley during July 2020

Before the predator removal operation, no kākā were detected on camera in the Perth River valley. Kākā were first encountered by our field rangers in the field site in August 2019, after the completion of the operation. Adults and juveniles have since been detected in the camera network on several occasions, by 12 different cameras throughout the site.

In June 2020, two of our field rangers captured the footage below of a kākā feeding on a rotten standing tree trunk near the confluence of the Perth and Barlow Rivers. Since September of this year, our team has reported increasing sightings of kākā within the same area. In November 2020, kākā were seen for the first time in both the Teichelmann Creek and Lower Barlow areas.

Kākā nest in holes in tree trunks. This makes them extremely vulnerable to predation by stoats, which can kill eggs, chicks and incubating adults in a single attack. A five-year study at Lake Paringa, South Westland, between 2010 and 2015, found that thirty times more kākā chicks were produced in an area after 1080 treatment than in an area where no 1080 was used.

We are therefore pleased, but not hugely surprised, that the successful elimination of stoats from the Perth River valley has led to an increase in kākā sightings. We look forward to seeing this population thrive!

Yellow-Crowned Kākāriki

Before the predator removal operation, yellow-crowned kākāriki were very infrequently heard by our field rangers during the course of their work. They are now regularly heard by field rangers up and down the Barlow Valley, and have been seen beneath the forest canopy on several occasions, including the sighting below in October this year.

Kererū

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A kereru caught on camera in the Perth River valley, June 2020

Before the predator removal operation, kererū were frequently sighted by our field team. However, no kererū were detected in our camera network until after the first phase of the operation. Over the last year, our team members have regularly seen kererū throughout the field site, and have even occasionally encountered large flocks of 30 or more birds!

Whio

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Whio in the Perth River valley, May 2020 (Chad Cottle)

Whio (blue ducks) were detected on just two cameras in the field site during 2019, before the predator removal operation, and on four cameras in 2020. The relatively low number of detections is not surprising, given that whio live on the river, and the camera network is primarily located in the bush! During the 2019-20 breeding season, whio ducklings were spotted on several occasions by members of the ZIP field team in the upper Barlow River area—the first time since we began work in the site in early 2018. In November 2020, rangers reported seeing whio ducklings in two tributaries of the Perth River.

Female whio are especially vulnerable to stoats during the nesting season, and rats and possums have been known to destroy whio nests and eggs, so the elimination of these species is expected to have a positive impact on the Perth River valley whio population.

Whio naturally live at low densities on the large, flood-prone rivers of South Westland, with an average of 1 pair per km of river. The modest increase in whio sightings and detections we have observed since the predator elimination is a very positive indication that the population is beginning to recover in the absence of predators.

Tauhou (silvereye)

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Two tauhou (silvereye) caught on camera in July 2020

Interestingly, silvereye activity appears to be highly seasonal, with dramatic increases in detections during the winter months, and reduced activity during the warmer months. So far, there has been no observable impact either way on the population as a result of the predator elimination.

Ngirungiru (tomtit)

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A female ngirungiru (tomtit) in the Perth River valley field site, June 2020 (Chad Cottle)

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A ngirungiru (tomtit) nest in the Perth River valley field site, December 2020 (Chad Cottle)

Ngirungiru activity also appears to be highly seasonal; however a general increase in detections can be observed following the predator removal operation. In February 2020, seven months after the operation, ngirungiru detections peaked at 22%, compared with 15% in February 2019.

Ngirungiru are frequently seen by our field team in all areas of the field site.

Kakaruai (South Island robin)

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A kakaruai (South Island robin) photographed in the Upper Barlow area (Chad Cottle)

Our team regularly see kakaruai around the Perth River valley. The bird pictured above is a regular visitor to ZIP’s bivvy in the Upper Barlow area.

The footage below was recently captured by one of our field rangers near a tributary of the Barlow River, where a friendly kakaruai cleaned her boot and gaiter.

Kārearea (falcon)

Kārearea are frequently seen and heard around the Perth River field site, including one that is regularly sighted near the Upper Barlow bivvy.

Ruru (morepork)

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Ruru photographed in the Perth River field site, July 2020 (Chad Cottle)

Ruru are occasionally seen and heard by our field rangers, and detected by our camera network.

The ruru above was photographed by one of our rangers in July 2020 near a tributary of Scone Creek, after it landed nearby looking rather unhappy to have been woken up!

Koekoeā (long-tailed cuckoo)

Koekoeā have been regularly heard throughout the Perth River valley during spring and summer 2020, particularly around the Upper Barlow River area.

Tūī and korimako (bellbird)

Camera detections of both tūī and korimako have increased during the last year, and both species are regularly seen and heard throughout the field site.

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