Friends of Flora - Predator Control

Stoats

The stoat is a member of the mustelid family, along with weasels and ferrets. It was introduced to New Zealand late last century to control rabbits and hares. The introduction of stoats is commonly regarded as one of the worst mistakes ever made by European colonists in New Zealand. Stoats are now by far the most common of the mustelids and are widespread in our forests. Stoats are extremely agile climbers and have a devastating effect on native birds by preying on adult and young birds and raiding nests for eggs. At Kowhai Bush, Kaikoura, a two year study in the late 70s showed that mustelids, mostly stoats, had robbed over 50% of 149 nests of native and introduced birds.

Rats & Mice

The rat is a good climber. It eats small animals, eggs, young birds and a wide range of native fruits, and other plant material. Mouse populations fluctuate with the availability of food - in the Flora area this is driven by the amount of beech mast available. It has been known for mice to eat all the beech mast present in a forest.

Possums

The Australian brush tailed possum was introduced into New Zealand in 1837 to establish a fur trade. It is estimated that the New Zealand possum population now tops 70 million and chomps its way through seven million tonnes of vegetation per year. Possums have eaten whole canopies of rata, totara, titoki, kowhai and kohekohe. Possums compete with native birds for habitat and for food such as insects and berries. They also disturb nesting birds, eat their eggs and chicks and impact on native land snails.

Control Area

Map of Friends of Flora's current contol area (opens in a new window)

We work in conjunction with the Motueka Area Office of the Department of Conservation (DOC). Between us our trapping programme covers approximately 5,000 hectares. We have 638 trap stations placed every 100 metres (a total of 64 kilometres of trapping lines), of which FoF monitors 460 monthly and DOC the remainder. Every station has a stoat trap, some also have a rat trap and/or a possum trap. No two trap lines are more than one kilometre apart. This is considered to be best practice for stoat control.

Friends of Flora planned line extensions (opens in a new window)

We are in the process now of finalizing our programme extension. We are extending the Flora programme to meet up with the predator control programme being carried out in the Cobb Area by two other groups – ‘Bush and Beyond’ and ‘Friends of Cobb’. It is planned to be completed within the next 5years. Between these projects, the protected area will be greater than 10,000 hectares, making it one of the largest volunteer trapping projects in the country.

Time Line

2001 Friends of Flora started in the Flora Valley
2003 Major trapping line extension
2004 Whio chicks released into the Flora
2007 First successful Whio breeding in the Flora since 1995
2009 DOC Kiwi Recovery Group gives go-ahead for Great Spotted Kiwi re-establishment

Bird count data

We have been doing bird monitoring from the outset of our programme. This involves our volunteers on our main core line, which is along the Flora Track, to take a one minute bird count – seen or heard, every 200 metres. This information is then plotted onto a bird count chart (opens in a new window)

We have a number of indicator birds that are important to our data. These include the robin, bellbird, rifleman, tomtit and grey warbler. After nearly 8 years of trapping, our data and anecdotal evidence shows all bird numbers have risen, some more so than others.

The Nelson branch of the NZ Ornithological Society has been doing a bird count in the Flora for the past 4 springs. It is carried out in November with a 5 minute bird count at every station through our main core line. They do it once in the morning and back again in the afternoon, and carry it out for 2 or 3 weekends. Their results are consistent with ours.

Traps & Bait

The traps we are using on the mountain are DOC 200’s, and recently, some DOC 150’s. All boxes are made to DOC current weka-proof and kiwi-proof specifications.

We are using mostly Victor rat traps for both the rats and mice, but we have been replacing them with plastic ‘Snap-e’ traps as the Victors age. We have found the wooden Victors swell in the damp weather and lose their sensitivity. The wire parts also have a tendency to rust, so this adds a further job for volunteers; having to clean and oil them. The plastic traps work as well as the Victors and are easier to set, making monitoring an easier and quicker job.

Friends of Flora’s possum trapping is in conjunction with the possum control programme DOC has been running in the Flora since 1993 for the protection of the endemic Powelliphanta hochstetteri hochstetteri snails, birds and flora in the area