Trapping Craigieburn Alliance

Volunteers working to restore flora and fauna in an outstanding natural landscape are heartened by the return of local birdlife. By Louise Porteous

Canterbury’s Craigieburn Basin, a biodiversity hotspot just 90 minutes from Christchurch, contains a wonderful variety of native habitats. Once home to te pouākai giant eagle, the region is of major cultural importance to Ngāi Tahu, a place of mahinga kai food gathering and ancient Māori rock art. 

The landscape consists of mixed beech forest and subalpine tussock grasslands with distinctive areas of weathered limestone outcrops, rising dramatically to the extensive alpine scree and snow-covered peaks of the Craigieburn Range. 

There are grey shrublands of matagouri, coprosma, and olearia, frosty alluvial terraces, fascinating limestone escarpments, braided rivers, and high country lakes and farms. The altitude ranges from 600m to more than 2000m. 

It’s no wonder this whenua is special to the many people who live, play, work, or holiday in the high country or who have whānau connections to this place. 

It was this sense of connection and a concern that the area’s biodiversity was under threat from introduced predators, such as mustelids, rats, possums, and feral cats, that led to the coming together in 2019 of many different groups to form the Craigieburn Trapping Alliance, a subcommittee of the Canterbury Environmental Trust. 

We signed a community agreement with the Department of Conservation that covers 62,000ha of public and private land from the Cass River to Lake Lyndon.

Volunteers have been working together trapping predators in the hope of making a difference. Five years later, we see the seeds of of their labour – people are reporting a louder and more varied cacophony of bird calls than a decade ago, when pest control was limited. 

Trapping has seen the successful fledging of kārearea New Zealand falcon. Credit Tim Rumble

The once familiar haunting cry of the kea – our beloved but endangered mountain parrot – had largely disappeared from the Craigieburn. But recent sightings of up to 17 birds on local stations and ski fields have raised hope and volunteer commitment. 

We hear and see korimako bellbird, miromiro tomtit, titipounamu rifleman, tauhou silvereye, riroriro grey warbler, pīwakawaka fantail, ruru morepork, and kārearea native falcon. Last summer, we had some exciting less common sightings – a pair of kākā, koekoeā long-tailed cuckoo, and toutouwai South Island robin.

Last year’s Bird of the Century Pūteketeke Australasian crested grebe also lives and breeds in the Craigieburn Basin. The publicity garnered through competition led to new interest in protecting the area’s high country lakes.

We received several donations through Forest & Bird’s Give a Trap website during the competition, including the gift of several traps from bird fans in the United States. 

All the stations have their own trapping and predator control programmes and are establishing a Craigieburn Catchment Group, working together towards a thriving healthier whaitua freshwater catchment. 

Some Craigieburn flora is also unique, being specifically adapted to the dominant landscape of unstable scree and rock ridges. 

If you see a blaze of colour in the forest between December to February, it may be the red flowers of the threatened pikirangi mistletoe. Its decline was once attributed to possum and habitat loss, but scientists now understand it is bird pollinated and therefore very sensitive to native bird numbers. 

It was particularly exciting to watch the three kārearea New Zealand falcon chicks that hatched at Kura Tawhiti Castle Hill rocks last year. The two females and one male juvenile successfully fledged and left the nest late December, having learnt the basics of flight and hunting on the wing. The trapline through the area has certainly contributed to this success and the addition of live capture feral cat traps should enhance their protection. 

A wide range of individuals and groups are working together to bring back nature to the Craigieburn Basin, including high country landowners and managers, local ski clubs, two school outdoor education facilities, Castle Hill Village, and holiday home owners. 

Here some of the projects the Craigeburn Trapping Alliance has been involved in.

TRAPPING

The main predators we focus on are feral cats, stoats, weasels, rats, hedgehogs, and possums. Monthly volunteer days are held on weekends through the trapping season from September to May to check and clear lines. Traps are positioned as high as 1200m above sea level. 

This work is bringing people together from all walks of life, with a common goal of enhancing the Craigieburn’s biodiversity and conserving its unique mix of fauna and flora. 

Volunteer days are a way to buddy up new members, discuss any issues, and share knowledge over a cuppa. Once confident in their abilities, many members prefer to pick up their own designated trap line so they can check it at their own convenience. 

Trapping in Craigieburn Forest Park dates back to 2006, when the New Zealand Conservation Trust partnered with the Canterbury Environmental Trust. Today’s much broader Alliance has built on this initial work, and many new traplines have been established over the past five years. 

The Craigieburn Trapping Alliance has more than 20 trap lines though Craigieburn Forest Park, public conservation areas, and adjacent station land. In total, there are more than 800 traps – mostly DOC 200s, a smaller number of AT220s, Sentinel, and Trapinators targeting possums, and live capture cages for feral cats.

Oli Jacobs, Thomas Bush. Credit DJ Matheson

HALO VILLAGE PROJECT

The Craigieburn Trapping Alliance has established a separate backyard trapping project at Castle Hill Village, a fast-developing high country settlement at 730m above sea level. It consists mainly of holiday homes. 

Over the past three years, this exciting project has grown from a handful of traps in backyards to an almost completed halo around the village. 

This project has also benefited from donations through Forest & Bird’s Give a Trap initiative, the wonderful legacy of the late Penny Willocks (see overleaf). 

Village residents, their friends and families, and members of the public have all donated traps to the project. We continue to infill with new traps when we can. 

With the help of Selwyn District Council, residents have also removed large numbers of douglas fir and other exotic trees. They have been providing an increasing habitat for local bird life by replanting with beech, kowhai, hebes, and other locally indigenous flora.

Volunteer day, Castle Hill Village, 2021. Credit Steve Greig

FERAL CATS 

The Celium Project is building a network of live-capture feral cat traps using wireless sensor technology, which allows immediate email or text notification to designated individuals when traps are triggered, ensuring a timely response. 

Piloted and now well established on land around Castle Hill Village, the project has been extended to Castle Hill Station, Flock Hill Station, the Enys block, and has been most recently trialled at Grasmere Lodge, joining the same system run by DOC in Arthur’s Pass National Park. 

The aim is to increase coverage along the Great Alpine Highway SH73 and surrounding land from Lake Lyndon in the south to the Cass River in the north. 

Station owners and managers have been generous in allowing traps and masts on their land and responding to trigger alerts. Increased coverage will enable us to involve other stations and land owners.

Phil Marsh and Liam O’Donoghue setting a live capture feral cat trap. Credit DJ Matheson

WASPS 

Our volunteers also participate in the annual Wasp Wipe Out coordinated by a very dedicated local as part of the national Wasp Wipe Out collaboration with Conservation Volunteers New Zealand and DOC, baiting a large network of wasp traps though the Craigieburn Forest Park and adjacent areas.

EDUCATION AND MONITORING 

The Craigieburn Trapping Alliance organises local trapping and monitoring workshops for its members that are also open to the public. Earlier this year, a fiveminute bird count course, run by Nelson Marlborough Institute of Technology and DOC, was held over a weekend in Castle Hill Village. 

We have access to long-term bird counts at a number of sites in Craigieburn Forest Park, some of which date back to 1978–82. This was compiled by University of Canterbury Emeritus Professor Dave Kelly et al, and this data really helps inform our work. 

Any data we collect is added to TrapNZ, a national database available to all trapping groups but also used by DOC. In the year to 30 April 2024, we carried out 6608 trap checks and caught a total of 940 mammalian predators, a success rate of 14%, almost double the success rate of 2021/2022. 

We know the number of predators caught isn’t a true measure of success. The Alliance is working hard on carrying out better monitoring, buying new equipment, and developing volunteer skills. 

Last season, we established a small number of new monitoring lines that use tunnels and tracking cards to identify predators in the area. The use of cameras is increasing our knowledge of pests, their behaviour, and trap placement. 

But as always with volunteer-led conservation mahi, there is still much more to do. If you would like to support our work (or any other local trapping project), please donate a trap via Forest & Bird’s Give a Trap website.

Louise Porteous, chair of the Craigieburn Trapping Alliance.

Louise Porteous is chair of the Craigieburn Trapping Alliance.