Measuring progress.
In September 2015 Te Anau based specialist, Iris Broekema, conducted a programme of native bird monitoring for the Trust to determine a base line across the project area. She will repeat this process annually to help measure progress but already anecdotal reports from many of the Hollyford’s visitors suggest bird numbers have risen markedly throughout the initial 900 ha operational area shown as ‘Stage 1’ on the map above.
The Stage 1 area has 124 stoat tunnels which have now been checked and their traps reset 5 times for a combined catch of 17 stoats. Six were caught in the first round for a trap catch rate of 4.8%, just within the Trust’s target of maintaining the rate below 5%. Subsequent rounds have seen catch rates vary between 1.6% and 3.2%. It has been heartening to see targets being met to provide protection for native birds through their full summer breeding season.
Over the same summer season we have filled the Stage 1 bait stations twice, once in November and again in March. We used Pindone pellets for the initail fill to bring rat tracking rates down from 38% to 18% but by March they were back tracking at 38%. We wanted better results so experimented by lowering the baitstations and trialing 2 different toxins in separate blocks - Pindone in one block and Diphacinone in the other, both being first generation anticoagulants.
Monitoring after the second fill confirmed Pindone the clear winner with Diphacinone having little impact and tracking rates in the Pindone Block lowering to 5% with a single rat indication in 1 tracking tunnel near the block’s boundary. This Pindone result fell within the Trust's target range and was particularly pleasing given the trial was conducted at a time of year when the forest has abundant food sources available for rodents.
When filling the bait stations we also undertook possum control using Feratox, a Cyanide based toxin that kills extremely quickly once ingested. Over the course of the 2 operations 52 possums were found dead next to bait stations – 47 in the first operation and only 5 in the second. These figures suggest that possums are well under control within the stage 1 area. We hope to confirm this with the results from specific possum monitoring that has recently been done.
|