ONCE EACH QUARTER the Auckland Regional Council run this
meeting and in June the topics were:
River/Te Henga Wetland Willow Control programme.
Island rats, a success story:
Control in Bush and Natural Areas A new perspective on Contracting
Te Ngahere in partnership with Auckland City.
Of these the
most interesting from a Barrier perspective was the Rakino Island rats.
This was an operation carried out by the Auckland Regional Council not
Department of Conservation and is particularly interesting being the
first rat eradication on an inhabited island.
Most of the
146 hectares is private property with 75 dwellings although there are
only 35 permanent residents. The eradication was done using 750 bait
stations on a 50m x 50 m grid with three lines along the cliffs. All the
offshore rocks and islets were done as well. The stock wasnt removed
instead the bait stations consisting of novaflow drainage pipe was
buried in the ground with a clod of kikuyu and soil over the top but
with the ends exposed.
bait was used and re-baited every 3 weeks until no more was taken. Once
this occurred the drainflow was replaced with tracking tunnels with
inkpad cards to indicate the presence of rats. Brodificoum was still
used as the bait so that if there was a rat present it would soon
succumb. A contractor was hired to set up and bait the stations until
there were no apparent rats present and then local volunteers took over
monitoring the tracking tunnels.
animals that succumbed to the bait other than the rats were turkeys and
sparrows. It has now been two years since the last rat on the island but
precautions are still taken at the potential points of entry. The ferry
wharf, barge ramp and boating visitor bays have bait stations and traps
maintained. Both barge and ferry operators maintain bait stations and
traps on their vessels and the rat free status of the island is
eradication there has been no explosion in the mice population which had
been expected after their principle competitors had been eliminated..