It is hard to believe that the dreaded possum, scourge of our native forests, orchards and rose gardens, was once a protected species! The Pukenui Forest Trust is currently removing as many possums as it can, using state-of-the- art trap and poison technology that is currently available.
Possum removal in the forest has been on-going now for several years, and the forest health has improved noticeably. One of the favourite foods of the possum in winter are the flowers of our beautiful kohekohe tree. This species is classed as sub-tropical and flowers in winter when there is not much other food about. Each flower has a small amount of nectar in it, which the possums love. Now, for the first time in quite a while, the kohekohe trees have flowered uninterrupted and are now setting seeds.
Gerry Brackenbury, ranger, and volunteer Marcus Bax, both involved in the early days of the Trust, beside a hundred modified bait stations ready to kill rats and possums in the forest.
Another pest that has been chomping into the lower forest canopy are goats. Again, these wild animals have been living in Pukenui Forest for a long time, and in the early days of the Trust, professional hunters have removed up to 500 animals. This will allow the trees, the shrubs, the ferns and even the orchids to flourish once again.
Feral goats can have major effects on forest under-storey because of selective grazing pressure on preferred species. Goats can devastate the forest under-storey of preferred sites when undisturbed for long periods.
A feral goat herd lived above the Whau Valley dam reserve. Private-landowner control initiatives are reducing this population and it is considered that their control is relatively easy to achieve.
There is some good news re the goat control programme. By July 2011, the cullers had taken out up to 400 animals and the forest recovery is already starting to show.
Another major animal pest in the forest are rats. We have two species of European rats in NZ, rattus rattus and rattus Norvegicus, and between the two of them, they eat practically everything, including seeds, fruit, insects and birds eggs.
In the early days, the combination of possums and rats has seen the almost total disappearance of native birds in the forest, particularly our beautiful native pigeon (kereru) and tui. These have been reduced to just a few birds when once they could be counted in their thousands. The pigeon is now the only bird left that has a crop large enough to cope with large fruiting trees like the taraire and puriri. If the pigeon disappears, what will spread the seeds of our trees?
The Pukenui Trust restoration of the forest programme has turned this around and the birds in the forest are returning.
Finally we cannot talk about pests and predators without mentioning the dreaded stoat. This was probably THE most stupid thing early colonists did to bring into the country this born-again killer. Stoats are highly intelligent predators which can swim, climb trees and leap tall buildings! This member of the mustelid family is the main reason why our kiwi had just about disappeared. Along with uncontrolled dogs, stoats kill kiwi on sight, especially kiwi chicks. We will be targeting stoats in our pest-control programme using a trap called a DOC 200. These will eventually cover most of the forest and, hopefully, within the next two years kiwi will be returned back to Pukenui Forest where they belong and can safely roam filling the night with their unique call.