An extensive network of nearly 500 possum traps extends
right across the 2,000 hectares of the northern forest block in East Harbour
Regional Park (EHRP) using two types of kill trap – Possum Master and Timms
traps. These are baited with long lasting cereal bait and an attractant made up
of flour, icing sugar and spices is spread around the traps. Traps are checked
by volunteers fortnightly in most cases and monthly where catches are falling
to very low levels.
In 2012/13 60 DOC200 stoat traps were added to possum traplines within and around the Mainland Island.
EHRP Catch data and bait consumption
YE April 2015
In our 11th year of trapping another 269 possums
have been dispatched bringing the total so far to 3538. The last 3 years have
shown small but steady increases in possums caught. It is uncertain whether this is a worrying
trend or perhaps just a reflection of increased trapping effort in some
areas. Given the very high rat numbers
experienced since the beech mast last season and increased targeting of possum
lures by rats, a lower catch might have been expected in 2014/15. However the
only objective measure of possums in the forest is the RTC monitor, which was
last done in 2013 (2%). Time for another monitor?
Catch per trap again confirms what we have already observed
in previous years that the eastern and northern boundaries are the source of
the highest number of possums. A record of 17 possums was made on one single
run on the south end of the Eastern Ridge this year. We need to give thought to
strengthening these boundaries especially with regard to self-setting traps.
Mustelid catches remain low and similar to the previous 2
Rats are only bycatch in possum and stoat traps and
increased hugely this year following the beech mast. However huge numbers no
doubt got away based on the number of non-toxic lures taken from possum traps.
Feral cats have not been targeted in the last 2 years.
Rat Bait Consumption
at Possum Traps:
As expected following the high beech mast, consumption of
ditrac blocks at possum traps has soared to 8000 blocks this year. This matches
the high reached in 2009/10 though still below the peak in 2006/07.