Pest Control

This project was established in 2014 after local landowners realised the impact introduced pests were having on the Lower Hollyford Valley – the birdsong was gone, and the canopy was collapsing, with the more palatable species such as southern rātā and fuschia being browsed extensively to the point of dieback. With support from the Department of Conservation, the locals decided they wanted to do something about it – to bring back the birds and to bring back the bush.

In order to restore and protect the native biodiversity of the lower Hollyford Valley, the Hollyford Conservation Trust undertakes intensive predator control over an area of 2600 ha, thereby creating a ‘mainland island’ sanctuary where mammalian pests are kept to very low levels. This pest control operation enables native flora and fauna to recover, and halts the browsing on canopy trees by possums, thereby giving birds and the forest a sustained chance to re-establish and flourish.

Our pest control network is serviced by over 200km of lightly cut and marked tracks, which require regular maintenance to keep them serviceable. 

Catches to date

Stoats

Rats

Mice

Weasels

Pest control operations

Stoats and Weasels

Stoats and weasels are controlled through an intensive grid of more than 350 DOC200 traps, set at 400m by 200m intervals, and every 100m along the coastline. These are typically baited with fresh rabbit meat and a chicken egg. The traps are serviced 7-8 times per year, or sometimes more if required and funding allows.

As of August 2020, 546 stoats and 2 weasels have been caught within the project area.

The Trust has set up a new trapping loop to protect the tawaki/Fiordland crested penguin breeding colony to the north of Martins bay. Tawaki chicks and sick or injured adults are vulnerable to predation from stoats when ashore during the breeding season, and when moulting. To protect tawaki (and other birds and animals in the area), stoat A24 traps have been set every 100m along the coast to the north of Long Reef, and every 200m over the ridge back to Martins Bay. This project has been funded by the Cliff Broad Memorial Fund. Please see the Cliff Broad Memorial Project for more information. 

Rodents

In our project area we use a grid of more than 2100 bait stations to control rodents and possums. The bait stations are located every 100m throughout the project area so that there is at least one bait station in the home range of every rat.

Pre-season rodent monitoring is undertaken to determine rodent levels in the area. Bait is typically put out from August to October to coincide with the start of the bird breeding season, and used thereafter to control rats based on subsequent monitoring results.

Rats are also caught in our DOC 200 traps. To date (August 2020) 2391 rats have been caught in the traps.

Brushtail possums

Until recently, possums were considered pests due of their effect on native flora, but they are also predators of native birds. Possums are known to feed on birds’ eggs and invertebrates, and have been recorded destroying nests of kererū and killing both adult and young fantails. Possums also restrict the food sources of insectivores such as tomtits and robins by predating on invertebrates.

Aerial 1080 drops in the lower Hollyford have been instrumental in the control of possums. Together with ground based control undertaken by the Hollyford Conservation Trust, possum levels have been reduced to very low levels, and this has allowed palatable species to recover, thereby restoring an important food source for native birds and other fauna.

When required, possums are controlled using Ferratox bait which is put in the bait stations.

Possum monitoring is undertaken every few years using the Possum Return Trap Catch method (RTCI). Through aerial 1080 drops and ground based pest control, the RTCI has dropped from an estimated 35-30% to 0.68% in 2018.

Rodent monitoring

Rodent monitoring is undertaken a minimum of four times a year in February, May, August and November, in line with DOC’s rodent monitoring at adjacent sites. We have a network of fourteen monitoring lines each with ten tracking tunnels across the project area, as seen in blue on the map below. The results inform our pest control operations.

Aerial 1080 pest control

DOC’s Battle for our Birds (BfOB) Tiakina Nga Manu programme has undertaken aerial 1080 pest control in the Hollyford Valley in 2015, 2017 and 2019 targeting possums and rodents (with an anticipated stoat secondary kill).  The September 2015 operation encompassed 18,000 ha, which was expanded to 43,000 ha in September 2017 covering both the Lower and Upper Hollyford Valley. Both aerial operations included the project area and have been shown through monitoring to have had a beneficial knock-down of possum, rodent and stoat populations within the treated area there. In 2019 the area was reduced due to budget constraints. The middle Hollyford was not treated and the lower Hollyford was reduced to the project area (2600ha) plus a 1km buffer – approximately 5000ha in total.

1080 is highly controversial, yet we regard it as the lesser yet necessary evil in our fight to maintain the native ecology of the Hollyford Valley.

Please see the following links in the discussion of the effects and efficacy of 1080.

Parliamentary Commissioner for the Environment – Evaluating the Use of 1080

Parliamentary Commissioner for the Environment – Evaluating the Use of 1080 Update report, July 2013

We want to see a healthy and thriving native ecosystem in the lower Hollyford Valley, with diverse and abundand bird life free from the risk of predation by possums, stoats and rats.

Our Vision

To protect, enhance and restore all native flora and fauna for the enjoyment of all, today and for generations well into the future.

About The Trust

The Hollyford Conservation Trust was formed in June 2014 to establish a ‘mainland island’ sanctuary in the lower Hollyford Valley, in partnership with the Department of Conservation (DOC) and other stakeholders.

Pest control

This project was established in 2014 after local landowners realised the impact introduced pests were having on the Lower Hollyford Valley – the birdsong was gone, and the canopy was collapsing, with the more palatable species such as southern rātā and fuschia being browsed extensively to the point of dieback.

Bird translocations

One of the key long term aspirations of the project is to return species that once lived in the project area but have become locally extinct.

Cliff Broad Tawaki Project

The Cliff Broad Tawaki pest control project is a trapping line along the rocky coastline to the North of Martins Bay to protect Fiordland crested penguins/tawaki during the breeding season.  This project is funded by a generous donation from the Broad family in memory of their father Cliff Broad, who had a special bond with the Hollyford Valley and Martins Bay.

Latest News

2019 annual bird monitoring

2019 annual bird monitoring

The results of the 2019 bird monitoring show birdlife in the valley has increased significantly since intensive pest control began in 2015.

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February 2020 floods in the Hollyford Valley

February 2020 floods in the Hollyford Valley

Early February brought record rainfall to the Hollyford Valley, causing signficant damage to the Hollyford and Milford roads, as well as causing large slips and damage to tracks, huts, and the Trust's own infrastructure. 1,000mm of rain fell in a 60 hour period in...

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