Predator control programme

Cornwallis peninsula predator trapping

2018 has been a successful year for the ongoing Cornwallis predator control programme.

Figures released for the year up to November 2018 show a total of 261 predator mammals have been exterminated in area. That total is made up largely of rats (232) but also includes some mustelids (18), such as stoats.

Possum activity on the peninsula has been greatly reduced in recent years. There have been minimal catches and little evidence of bait being taken by possums. However, as the warm weather continues, signs of possum activity is expected to rebound at the northern end of the peninsula in the new year.

Rats and stoats are a major problem as they breed prolifically and have voracious appetites. In ideal conditions, a rat can produce 10 offspring every eight weeks (20-30 times faster than native birds) and eat about 15 grams of food per day. A stoat needs to eat the equivalent of 12.5 fantail chicks every day to survive.

The amount of predators trapped or killed represents a lot of work by a small team – led by local residents Alex and Rose Duncan – who aim to rid the peninsula of all small predator mammals.

Once a confirmed kill is made, the results are recorded on a specially designed smartphone app that stores the totals and location, adding it to the database for the area. The app was created and run in conjunction with the University of Auckland, which – along with Auckland Council – have been strong supporters of the programme.

One benefit of the new technology is the ability to map the catches recorded at each of the traps – giving a “heat map” for the area (see above). As graphically shown in the map, the most predator action is being recorded either in the areas where people fish/live or areas with known bird nesting sites.

An important beneficiary of the trapping programme has been the colony of grey-faced petrels at the southern end of the peninsula. These birds are largely nocturnal and burrow into the soft cliff face earth to create their nesting areas – making them especially vulnerable to predators.

However, a concentration of predator traps around the nesting area has improved the safety of the young birds. In recent months there has been significant activity recorded on cameras in the area, showing evidence of young fledglings in good condition.

Other native species also benefit from reduced predator numbers, including piwakawaka, ruru, riroriro and even wetas.

There are several priorities for programme in 2019, including the need to widen the pool of volunteers involved, and encouraging households on the peninsula to purchase and maintain a trap on their property. The aim is to have 50% of Cornwallis dwellings with a trap by end of 2019 – or around 35 traps.

It is also hoped that in the near future, organisations like the Department of Conservation may see the peninsula as a suitable location for possible native bird releases.

For more on the Cornwallis predator control programme, see our Environment page.

Cornwallis Beach Tweets