December 2017
Photo - Whio with 5 ducklings in the Karamea River
Friends of Rotoiti meeting
All welcome - 9.30 am DOC Meeting Room, Saturday 9 December. Nik Joice will update us on biodiversity work. DOC will provide lunch.
ROTOITI NATURE RECOVERY PROJECT
2017 TECHNICAL ADVISORY GROUP (TAG) MEETING NOTES
Peter Hale (FOR TAG Representative)
The following is a summary of the main points of interest to FOR members.
RNRP Mustelid control and monitoring
- Decrease in captures since the 2014/2015 mast.
- 3 juvenile weka caught in last year.
- 30 animals caught by non-target body part (snout, leg, tail) including rats, cats and hedgehogs.
- Early results of a trapping trial in Big Bush shows that oestrus bedding lure may be better than Erayz.
- Over the last 2 years mustelids have been kept below 5% as indicated by tracking tunnel monitoring however this may not be benefitting kaka as previously thought.
Kaka
- This raised lots of questions.
- During the 2015 breeding season 29 relocated historic nest sites were monitored for 1 – 2 hours each. Only 2 were being reused.
- The method used for checking nest occupancy may not have been effective enough. It may require climbing or camera monitoring however the picture for kaka numbers isn’t looking good.
- The birds caught by Project Janzoon staff in 2015 showed a strong male bias, 7 to 2, so it appears that the females are still being predated on the nest.
- Maybe the tracking tunnel monitoring of mustelids is not sensitive enough, ?trap-shy animals, ?network of single-set traps is not sufficient, maybe kaka encounter rate monitoring may only measure how noisy they are.
- Not sure what has changed, they appeared to have been doing well at first but are not now.
- Kaka breeding needs to coincide with effective protection, if we assume that they are only vulnerable while on the nest.
- The control area is probably not large enough and probably not protecting enough nests.
- They may have taken a hit during the A24 trial in 2012/2013 which was ineffective and stoat numbers got high.
- The decline may be a reflection of the kaka population in general.
- Kaka like other species need landscape pest control. The timing of the last 1080 operation was wrong for kaka. They breed the year following a mast so two 1080 operations in a row may be the answer, the first in a mast year then the second in the following year.
- DOC Nelson Lakes is to make a funding proposal for more intensive trapping involving a change to double-set DOC 200’s, more monitoring and regular 1080 operations over a larger area.
- There will be no more translocation of kaka from Nelson Lakes.
Responses to pest control in Nelson beech forests
- Kelly Whitau from Canterbury University undertook this study as part of her Master of Science in Ecology degree.
- Used long-term (2002-2015) tracking tunnel and 5 minute bird count data from areas of beech forest at 6 treatment and 1 non-treatment sites in Kahurangi and Nelson Lakes National Parks.
- The objective of the study was to determine the effect of different pest control methods (trapping, and poisoning with diphacinone, pindone or 1080, both ground based and aerial) on ship rat and common forest bird populations, particularly how these effects are influenced by altitudinal gradients and beech masting events.
- The only control method that effectively reduced ship rat abundance was 1080.
- The 12 most common bird species detected across all sites included 4 introduced and 8 native/endemic species.
- Most native/endemic bird species showed significant declines in response to increased rats and the effect was reduced with altitude showing that high altitude is a refuge for birds to escape predation. This was very evident in rifleman and brown creeper.
- There was a clear relationship between stoat control and increased rat numbers.
- The data showed a slow decline in the bellbird population at Rotoiti since the peak following the successful brodifacoum operation (pre 2002).
- Competition from introduced birds and wasps was also included in the research.
- Her finding are being published in 2 papers which will be available soon.
Rodent control tools
- Emma McCool presented the results from the most recent ground based operation using diphacinone D-block in 2016.
- Used Philproof bait stations with baffles and Pestoff tunnels in a 100 x 50 m grid in the core and baffled Philproof stations in the rest of RNRP in a 100 x 100 m grid. The bait was replenished twice.
- Tracking tunnel results showed the operation failed with no difference in rat tracking between the treated and non-treatment area.
- Bait take was highest in the core and decreased with altitude.
- Bait station comparison, 42% vs 22% Pestoff to Philproof.
- Mice are immune to Diphacinone
- Able Tasman has also had 2 recent failures using both Diphacinone and 1080 in bait stations.
- The rat issue in RNRP has not been solved since inception and this needs to be communicated to the public.
- Discussed the use of A24’s, successful at Boundary Stream but did not need excluders. The BFOB TAG group has recommended that A24 use be stopped in presence of kea and kaka as they are being killed.
- Rats were supressed after the 2014 BFOB 1080 operation but did not persist.
- Suggested doing the whole lot with 1080 but with a better swathe and a higher sowing rate than that used in 2014. Include Big Bush as well.
- It was decided not to persist with ground –based poisoning as it has never been effective.
FOR presentation
- I gave a presentation on behalf of Friends of Rotoiti.
- Presented the interim results of our run-through vs DOC 250 trial showing the 250’s baited with Erayz caught more stoats but the run-throughs still caught at 2:1 but mainly non-target species.
- Showed our mouse excluder design. Kerry Brown considered the interim results to be very interesting and strongly recommended we make the trial official under a DOC SOP. It raises the question of the importance of bait integrity.
- DOC Nelson Lakes is intending fitted excluders to all of their traps, >800.
- I outlined the GSK project and how it has generated increased FOR interest and membership.
- I expressed my concerns relating to the relationship between DOC and Community Groups in general. There needs to be more cooperation, discussion and guidance. There are some anti-DOC and anti -science barriers and these need to be addressed if we are to make meaningful gains. Craig Gillies indicated they had made big gains in the Waikato
- John said FOR was their “Blue sky research unit” to pilot and test new ideas that RNRP is not resourced for. We have a strong relationship and going from strength to strength.
Cat control
- Discontinued by DOC at the end of 2015, picked up by FOR.
- PAPP was discussed but the technique is not being used a lot, difficult to trial in presence of kea.
- Remote monitoring of cage traps is the answer but they must have an inbuilt failsafe. Cages that open at both ends are better than Havahart’s.
- Cats travel a long way but little altitudinal difference.
Trail cameras as a monitoring tool
- Craig Gillies presented some of his recent work in the Whangamarino wetland that is about to be published. Theft was an issue.
GSK
- Pat Van Diepen presented this.
- In the bigger picture translocations are not favoured so this will be the last attempt to make this population viable.
- Main reason for the local GSK population could be for testing the success of pest control. It will never be used as a source population for translocations elsewhere.
- Looking after the original populations is still the DOC priority.
Possum Control
- Still enjoying low numbers at Lakehead following the 2014 BFOB 1080 operation.
- The trial of terracotta clay inserts in the sentinel clips has been put off.
- Sentinels with covers appear not to be a risk to kea however the tree they are mounted on must not have any limbs underneath.
- May be benefits with deactivating them at critical times of the year.
- Sentinel lines have significantly reduced the possum population in Big Bush.
- Mistletoe monitoring shows an excellent response.
Sharing RNRP’s stories/research
- It is important to get the stories out there so senior DOC managers and community groups understand the experience and science results.
Weta - photo Drew Hunter
Whisky Line - Drew and Marg Hunter
As well as clearing 7 possums and one rat from the traps Drew and Marg saw lots of wasps and took this photo - the weta was resting under the corflute cover of a sentinel trap.