Ulva Island: Exploring an Island Paradise

Fog beginning to burn off on Ulva Island

This is the middle of winter and I am at the far southern end of New Zealand.  Fortunately, the climate is moderated by the Southern Sea and we had a beautiful day to explore the island.  After the fog lifted, the temperatures climbed into the fifties which made for an absolutely perfect day for tramping (hiking) the island.                            Ulva Island is the largest of several small islands situated in Paterson Inlet (Te Wera a Te Wera – everything has a Maori name) near Stewart Island (Rakiura).  The majority of the island is part of the Rakiura National Park and is managed by the Department of Conservation – DOC as an open sanctuary – a place where native plants and birds can live in a safe environment and the public can enjoy them.  The remainder of the island at Post Office Bay is privately owned.         Ulva Island was reserved under the Land Act 1892 for the preservation of “native game and flora”.  It is one of the earliest reserves of this type in NZ and is very important to conservation and tourism.     

Umbrella Moss

  

NZ is unusual in that there are no native mammals that are predators to birds.  In their absence native birds took over the niche of “top predator”, with some growing very large and losing the ability to fly.  People introduced animals that today still play havoc.  Wild cats, possums (not like our opossum, this one is cute and furry), and rats attack birds, their eggs and chicks.  They hunt and eat lizards and insects.  Possums and deer destroy foliage and rats will eat just about anything, taking the nutrients needed for the wildlife to breed.             Thankfully, the mustelids, rabbits, and mice which have plagued the remainder of NZ were never established on Stewart Island.         On top of this, vigorous introduced plants have replaced native ones.  Foreign plants continue to be introduced to NZ as garden specimens.  One in ten “escapes” and becomes a serious threat to native plants in the wild, where they are now more introduced than native plants.          It is a huge job to stop these invasions, but island sanctuaries can help.  Once week and pests are cleared from an island, it becomes a haven surrounded by a huge protection, safe to reintroduce native plants and animals.  Ulva Island is partway through this process.                               For some insight into the rat infestation, rats can swim up to 700 meters and can arrive from even the cleanest boats moored offshore.  They can stow away in luggage and so visitors are asked to thoroughly check bags for hitch-hikers before stepping onto the island.  On average, one rat a year manages to hitch a ride and escape onto Ulva Island.  Ulva Island is protected by a carefully designed set-up of bait stations and rat traps.   It is hoped that any new rats would soon be lured in to eat the poison baits or get caught in traps.     

      

If any rats are caught, they are sent to the University of Otaga for DNA testing.  A few years back, a female rat made its way to Ulva Island and within 8 months, had over 4,000 offspring.  The DNA testing showed that all the rats caught came from that one “mother rat”.