Orokonui Ecosanctuary
South Island saddleback
In the Orokonui Valley, close to Waitati, an ambitious programme has been undertaken to remove all introduced mammalian pests from inside a new exclusion fence. The 8.7 km long fence encloses an area of 307 ha. and it is estimated that there may have been 2,000 possums, prior to pest control. Removal of possums has been part of the programme to eradicate all introduced mammals and create the Orokonui Ecosanctuary.
Possum eradication at Orokonui commenced in August 2007 and used several different techniques. Traps, dogs and poison were all employed at various stages of the operation. Leg hold traps, with soft jaws to catch live animals, were used first of all and caught 800 possums. A further 100 possums were caught with the help of a trained predator detection dog Jess, belonging to Elton Smith, Conservation Manager. Finally, the poison Pestoff 20 R was used. Pest off targeted the 3 species of rodents with the sanctuary but possums were also known to consume the bait. Two aerial drops occurred in August and September 2007. The first application was applied at the rate of 12kg/hectare and the second at 8kg/hectare. Within 20m of the fence line, in dense windrows and in grasslands, the bait was hand broadcast.
Pestoff contains brodifacoum, an anticoagulant poison that affects possums as well as rodents. Poisoning was completed 2 months after the trapping in September 2007.
Peripatus novaezealandiae (a velvet worm) with newborn
Twice during the following year, in July and October 2008, a pest contractor was employed to search the Ecosanctuary for any remaining possums. Four handlers using teams of trained fox terriers hunted the entire area. No possums were found. Since November 2007 Jess has also clocked up several hundred hours walking throughout the sanctuary without locating a possum.
This information was supplied by Elton Smith, Conservation Manager for the Orokonui Ecosanctuary.