Pest Control
Foreign pests introduced to New Zealand with human colonisation have seriously depleted native wildlife and caused many extinctions. Of the endemic birds and other wildlife that remain, many are endangered. Experience in New Zealand has shown that with good control of predator and competitor pests, it is possible to see a 50% compounding increase in birdlife every year. The Trust is motivated toward achieving this goal.
Due to its size and maturity, Puketi Forest provides good wildlife habitat for a variety of native wildlife species not currently in the forest, but found there historically. This means that future translocations could be successful. The first steps in a successful reintroduction strategy are to establish effective pest control and to demonstrate that adequately low pest numbers can be maintained.
What pests are present?
Puketi Forest Predators, by Cecilia Russell. Click on the image to see more about pests on the Puketi Kids website.
Mustelids (stoats, ferrets and weasels), feral cats, rats, possums, hedgehogs, pigs and dogs all predate birds or their eggs and other native animals in Puketi.
Rats, possums, pigs, goats and mice consume the plants of the forest and compete with birds and other native wildlife for food.
All of these animals have been brought to New Zealand by humans.
Trapping
Since 2003 the Trust’s focus has been on the eradication of cats and mustelids from 5500 ha in Puketi Forest (called the 'management area') and the removal of rats from a 650 ha core area within this. [See Map of the Management Area]
![[See Map of the Management Area]](img/map_man.jpg){kind=link}
This is being undertaken using traps and contractors and has the goal of maintaining pest numbers at less than 5% tracking for all species. To achieve this, nearly 100 km of track has been cut through the forest and 790 stoat traps (Fenn and DOC 200’s) and 204 cat traps (predominantly SA cat traps) have been placed at 702 trap sites along 10 trap lines. These traps are placed at 100 m or 200 m intervals along each trap line and baited with salted possum meat or eggs.
In addition 2300 rat traps (Victor Supreme) have been placed on a 100 metre by 50 metre grid network within the core area. Rat traps are baited with peanut butter or Ferafeed 213, a proprietary possum and rat bait from Connovation Ltd.
As well as stoats and cats, a number of weasels, ferrets, rats, hedgehogs and possums are caught in the stoat and cat traps. Some mice and the occasional stoat are caught in the rat traps.
Trials to discover more effective trapping methods are carried out, e.g. comparisons between bait type (salted meat vs. egg), trap type (Fenn vs. DOC200), and box construction (end entry vs. side entry).
Accidental casualties among non-target animals are a concern in any pest control operation. Stoat and rat traps are contained within boxes to prevent access by birds. Cat traps are mounted on tree trunks above kiwi reach. To date there have only been two non-target casualties, a kingfisher and a harrier caught in cat traps. This compares very favourably with estimated rates of secondary poisoning in operations using poison. No domestic cats have been caught.
All traps installed by the Trust meet the National Animal Welfare Advisory Committee’s guidelines for humane traps.
The Department of Conservation provides the principal effort for control of possums, goats, pigs and dogs. No wild dogs are known to be present. Most dogs that enter the forest are brought in by pig hunters. Control of dogs is therefore via education and permitting for pig hunters, and kiwi aversion training for their dogs.
Traps have been progressively installed since 2003 as shown in the following tables:
Stoat/Cat Trap Installation:
| Trap line | Date installed | Number of trap sites | |
|---|---|---|---|
| Stoat | Cat | ||
| 1 | October 2003 | 98 | 25 |
| 2 | 71 | 17 | |
| 3 | 45 | 23 | |
| 4 | 51 | 26 | |
| 5 | 42 | 21 | |
| 6 | November 2005 | 123 | 25 |
| 7 | 52 | 26 | |
| 8 | 49 | 25 | |
| 9 | November 2006 | 108 | 0* |
| 10 | 63 | 16 | |
* Cat traps will be installed on line 9 once a stoat trapping trial on that line has been completed.
Rat Trap Installation:
| Trapping area | Date installed | Number of traps |
|---|---|---|
| Plateau | December 2005 | 1300 |
| Te Tawa Stream | January 2008 | 1000 |
To see a summary of the numbers of pests trapped, go to the Trapping Results page.
Pest numbers are monitored using tracking tunnels. Results are shown on our
Pest Monitoring page.