Auckland Council Natural Heritage Fund 2013/2014. Final Report. Windy Hill Sanctuary Banking Biodiversity

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1 Auckland Council Natural Heritage Fund 2013/2014 Final Report Windy Hill Sanctuary Banking Biodiversity Windy Hill Rosalie Bay Catchment Trust 429 Rosalie Bay Rd RD 1 Great Barrier Island lovebirds@xtra.co.nz

2 Thank you for your support of the Windy Hill Rosalie Bay Catchment Trust Windy Hill Sanctuary Banking Biodiversity project. It has been an exciting time of ecological restoration within the 620HA sanctuary at Windy Hill and Rosalie Bay, south eastern Great Barrier Island. Since this grant was approved in October 2013, integrated plant and animal pest management continues to become more efficient and effective with innovative programmes, the action triggered cameras funded by the grant have recorded a wealth of species information, and our field team of 5 has weathered a miserable winter in the field wear funded through the grant. Outcomes to Key Objectives 1. Within the sanctuary we continue to sustain and improve the biodiversity of this area of Great Barrier and bank the conservation gains made since the project commenced in The biodiversity of the area is sustained by managing plant and animal pests at low densities which allows native species to thrive, and is improved by translocating new species as well as discovering rare species. Restoration, however, is not a straightforward business and progress is deeply affected by weather events, particularly droughts, and seasonal variations. This quote from our Bird Monitoring Report January 2013 by John Ogden : The large fruit and nectar feeders (kaka and tui) declined markedly in 2013, despite more kaka nests being found in the sanctuary than in previous years. Numbers of these species fell to levels not recorded since Kereru continued a slow decline in the sanctuary, but plummeted to zero in both control areas. Previous association analysis shows these three species tend to occur together, which suggests some competition for possibly limited food resources when high bird densities (as in 2012) are achieved. A full copy of the report is attached. Interestingly, as the summer progressed into autumn, conditions changed markedly in terms of food availability and we saw record numbers of kereru and kaka. The kereru photographed below were part of a 50+ flock with 100 being recorded in Rosalie Bay a few days later.

3 Red Crowned Kakariki Translocation Our application to DOC for a translocation of 8 birds to establish a breed and release programme was withdrawn mid 2014 and replaced by an application to expand the translocation to include 40 birds for hard release as well as the birds for the breed and release programme. Birds will be sourced from Hauturu and the translocation, which is planned for between March and May 2015, will be an exciting addition to the work of the Sanctuary. Kakariki are at critically low levels on Great Barrier and the breed and release programme, a first in the Auckland region, may well prove to be the way to arrest their decline and establish a self supporting population. Two red crowned kakariki were recorded in the Sanctuary in late summer and these birds may add to the gene pool of the released and captive reared birds. The aviary for the breed and release programme is complete with nesting boxes and bird perches to be added late this year. Thank you, EIF. Robins Over the winter we counted 7 pairs and a few single birds in the Sanctuary, down from 8.5 pairs post translocation release in While we are pleased to still have this many birds, the pattern of loosing birds through dispersal is similar to our earlier releases. This is the key reason that we are keen to research a different method of reintroducing species back into the Sanctuary forest. Four of our robins are still being reported on Hirakimata (Mt Hobson) and a pair at Kaitoke. Seabirds The second year of Seabird surveying by Jo Sim with her dogs was carried out in December The following is a summary of what was found : No Cooks petrels were found 3 new black petrel burrows found 1 black petrel found on surface 1 unknown burrow found to be determined A new grey-faced petrel colony found near Smugglers Cove New GFP burrows & chicks confirmed at first site 5 kaka nests detected by dogs at ground level in hollow puriri trees This map indicates where seabirds have been found in the Sanctuary over 2 surveys.

4 The presence of an increasing variety of bird species is a testament to the efficacy of our pest management. Lizards these beautiful creatures have become a feature species for the Sanctuary of the 13 species known to occur on Great Barrier 11 have been positively identified in the Sanctuary. Arboreal monitoring in 93 different trees between February and April this year identified the following: Species Number Percent Lizard 13 14% Weta 64 69% Other Invertebrates 18 19% Rat 42 45% Nothing 13 14% It is great to see so much life in the trees but disturbing to record the number of trees with rats. This does not necessarily indicate high numbers of rats as the tunnels were out for 3 weeks at a time and a single rat may visit a number of trees, but it does indicate how active these animals are in trees. Arboreal light foam tracking tunnels were placed in 93 trees for 3 weeks at a time The Sanctuary continues to manage pests to low densities as part of an integrated pest management programme with the goal of sustaining biodiversity. Below is a summary of culled animal pests to from January 2011 to end August 2014: Rats Mice Cats Pigs Magpies Wasps Rabbits nests nests nests nests 22 Total 11, nests 63 The figures indicate that with 4 months of trapping to go this will have been a big year for rats, a huge year for wasps, and increasing number of rabbits. Since pest management began in 1999, 44,000 rats have been trapped. Weed pests such as hakea, plectranthus, Mexican devilweed, jasmine, and pampas continue to be systematically removed. Aristea is being removed from gardens in the Sanctuary.

5 2. Research Developing innovative and adaptive management Since the introduction of toxins to the programme in 2005 the Trust has trialed a range of toxins mixed with trapping and measured the efficacy of the different methodologies. The goal of this programme is to find the most effective, cost effective, and socially acceptable way of managing pests at low densities with a focus on minimising toxin use and limiting potency. The table below shows the progression of methodologies and Tracking Tunnel indices. The Sanctuary is divided into pest management areas: LWH = Little Windy Hill, BH= Benthorn Farm, BW = Big Windy, and RB = Rosalie Bay. Contr=unmanaged control site. Date Management TT % annual average Events LWH BH BW RB Contr Trapping Only Trapping with 2 x 1 week pulses cholecalciferol Strikers 2006 Trapping with 2 x 3 week pulses cholecalciferol Strikers 2007 Trapping with 2 x 6 week pulses cholecalciferol Strikers Huge storms 2008 Trapping with 2 x 6 week pulses cholecalciferol Strikers 2009 Brodifacoum Brodifacoum Drought 2011 Trapping 50% & 50% 150gram Diphacenone Feb-May 2 x 20R brodifacoum perimeter track only Trapping 50% & 50% 100gram Diphacenone Feb-May 2 x 20R brodifacoum perimeter track only * Trapping 50% & 50% 50gram Diphacenone Feb-May 2 x 20R brodifacoum perimeter track only * Drought 2014 Trapping 50% & 50% 50gram In July Diphacenone Aug 2014 Trapping 50% & 20gram Cholecalciferol * Remained in brodi thru 2012 * I month pulse brodi to bring rats down It is clear that trapping only does not work sufficiently well to make conservation in the Sanctuary worthwhile. However, the current programme of 50:50 traps and bait is proving to work acceptably well. The low potency multi-feed bait diphacenone has been the principal toxin to mid 2014 and has now been replaced with cholecalciferol (VitaminD3) in 20 gram bags. This means that currently we are trialing the least toxic, most socially acceptable bait available which is, unfortunately, also extremely expensive. There is currently no brodifacoum use in the Sanctuary and this is likely to remain so. With climate and weather events, like droughts, so affecting the rat densities, adaptive management is essential. Traps are checked

6 monthly with the perimeter tracks checked fortnightly to maintain optimum management on our leaky edges. The main method of measuring the effectiveness of these programmes is through regular monitoring using tracking tunnels. The graph following shows the tracking tunnel results for the Little Windy Hill pest managed area within the Sanctuary. The difference between trapping and then the addition of toxins, is graphically illustrated with less marked variation in results and a much more consistent lower percentage with normal seasonal variances. The autumn rise in Mar 2014 was from a mast year for kahikatea resulting in abundant seed. This research into best practice in this habitat is particularly important to the future direction of pest management and the possibility of a feral cat and rat free Great Barrier. Work to date illustrates how ruthless and systematic the approach has to be to keep rats at low densities and to manage the ongoing reinvasion. Since 2011, Windy Hill and Glenfern Sanctuaries have synchronized their tracking tunnel programme. The graph below compares the tracking tunnel percentage indices between a fenced and unfenced Sanctuary area. GS = Glenfern Sanctuary, GSControl = Glenfern unmanaged control, WH = Windy Hill, and WH Control = Windy Hill unmanaged control. The purple lines represent the huge numbers of rats present in the unmanaged control site at Windy Hill compared to the lower densties in red at Glenfern. In this context these results indicate that the Windy Hill Sanctuary is managing to keep rats at remarkably low levels.

7 One of the difficulties with rat managment on Great Barrier is the presence of both kiore and ship rats. At both Glenfern and Windy Hill Sanctuaries it has been noted that as ship rats are kept at low levels kiore numbers rise and they appear to be able to persist. In May and June at Windy Hill this year each animal caught was identified - 59% of rats trapped were kiore. Negotiations are underway with Auckland University to engage a Masters Student to study the behavioral differences between the two rat types so that a better understanding of how to manage them may be gained. This has application for the entire Pacific where these two rats co-exist. Action Triggered Cameras - the three cameras funded by this grant have provided the field team with an extraordinary insight into the behaviour of the pests we are targeting and the species we are protecting. Cameras have recorded the emergence of a grey faced petrel from its burrow, watched its progress as it grew feathers, and came out nightly to exercise. Stations have been set up with a variety of rat lures and the responses from rats recorded (they like chocolate lure!), cats have been fimed approaching and being caught in trap. The new GoodNature self setting trap was filmed but performed poorly more work needed on this model for rats. Cameras have been set up on tracks to record activity which included rabbits, pigs, cats, a pheasant, rats and humans passing by. The recordings are being analysed and will be edited into short films which will be useful in determining future management methods. Worm Farms for processing used Bait between 60 to 80% of the bait deployed in stations is returned uneaten or partly eaten as it is replaced with fresh bait. Disposing of such huge quantities of bait at the local Landfill was problematic and so it was decided to trial putting the used bait into worm farms. Auckland Council supplied a bin, as did the Trust, but these were quickly filled so the field team built additional large worm farms using recycled pallets. The first samples of worm casting from the brodifacoum bait ( returned from the Council Biosecurity programme) and diphacenone have recently been sent for analysis to see if detectable levels of the toxin are present. 3. Creating and sustaining conservation based employment. Currently, five people are employed in the field team that undertakes pest management, the monitoring programme, threatened species habitat protection, and maintenance of the Sanctuary s over 80km of trapping routes. Another local person is employed as a part time administrator. The Sanctuary is managed by a volunteer and there are now two field volunteers. The Trust also employs a part time contractor to undertake the Auckland Council bio-security programme on Great Barrier. The wages from the field team make a significant contribution to the economy of the island with some 70% of the grants received by the Trust being paid out in wages. Since 1999 when pest management commenced over $1M has been paid in wages. The field team manager has now been employed for 12 years, the bio-security contractor for 15, our senior field worker for 9 years and our youth field worker for 2 years. Since 2010 the Trust has worked with the local social worker to target unemployed youth to join the team as there are few opportunities for young unskilled youth to gain training and work experience. The social well being of the team is profound as they experience sustained employment, working within a team, and making a valuable contribution to the biodiversity of the area. They have developed sufficient skills to be considered conservation professionals. The Trust highly appreciates the Nature Heritage Grant which funds wet weather gear, footwear, and tools that keep this team functioning all year round in a safe and comfortable manner. 4. Maintaining and expanding a comprehensive monitoring programme The monitoring programme involves a range of methods by which we measure the programme efficacy and species response to lowered pest densities. The programme has continued to evolve and expand over time and includes the following:

8 Birds 3 minute counts once a year and 5 minute counts every decade Lizards Onduline motels and lizard boxes - twice yearly ACO s (Foam covers) and 600 Onduline stacks once yearly (with Ecogecko- a Landcare Research project) - D-Minnow traps throughout summer - Foam refugia/tracking tunnel throughout summer - Arboreal tracking tunnels over summer Rats tracking tunnels 5 times a year Weta motels twice yearly Invertebrates under Onduline stacks twice yearly Seedlings in plots twice yearly Freshwater Streams twice yearly Bats bat detection boxes in 2012 Seabirds 6 acoustic recording devices Dec 12 Dec 13 Morepork 4 acoustic recording devices current Pimelea Tomentosa (threatened plant) biannually Some Monitoring Outcomes Birds Please find attached the bird monitoring report from December Lizards A range of methods are used to with monitor both geckos and skinks, ground dwelling, and arboreal species. In 2006, lizards were identified as a key indicator species in relation to rat densities. Not a single lizard was monitored in the first year of monitoring in our unmanaged control site with lizards present in 30% of Onduline stacks from the first month within the Sanctuary. The graph below illustrates how this percentage has grown over time. Of note is the dip in lizard numbers after the summer 2010 and 2013 droughts. This dip is replicated in our monitoring of weta and seedlings illustrating the impact of weather events on species. Lizard occupancy has generally risen since 2008 with a drop after the droughts in 2010 and Rats - Tracking Tunnel monitoring is carried out five times a year. The table of tracking tunnel percentages from January 2013 to date by pest managed area is below. Rat densities

9 rose through the autumn (April 2014) commensurate with the masting of kahikatea. Rat densities throughout NZ were high at this time. LWH BH BH Big Windy Rosalie Control Bush Paddock Bay unmanaged Jan Apr Jul Sept Nov Jan Apr Jul Sept Despite intensive and systematic management, rats densities continue to fluctuate they are driven by climate, weather events, and seasons that offer more food availability. Sanctuary indexes are still well below unmanaged Control densities. Pimelea Tomentosa this category C threatened plant has been monitored biannually since Following the removal of feral goats in 2004 the plant, which was identified by Ewen Cameron the botanist form Auckland Museum, started to die out because it was shaded out by recovering vegetation. Over thirty plants were fenced to prevent browsing by rabbits, vegetation kept clear of them, and kept under surveillance. As the Sanctuary area extended from 2006 a much larger number of plants were discovered in more open ground and this meant we could discontinue the intense monitoring and protection Many hundreds of pimelea have been counted making this the largest record of this species in the Auckland region. Pimelea Tomentosa - Adult plant and seedlings. A review of all monitoring outcomes is currently being undertaken by John Ogden and a report on the trends and patterns that have emerged will be completed in early Our monitoring programme continues to develop along with our capacity.

10 3. Community Involvement The community continues to have an interest in our activities and progress. Over 400 people receive our twice yearly newsletter. This last year has seen a steady number of people asking the Trust for assistance and to purchase equipment. The Trust Manager has also helped a number of applicants with funding applications and regularly takes visitors through the Sanctuary. The Trust is active in promoting the benefits of pest management and the vision of a rat and feral cat free Great Barrier though articles and presentations. The Trust manager also mentors other fledgling projects. Both Glenfern Sanctuary and Windy Hill work closely, and now share pest management methodology allowing a better opportunity to follow the different outcomes of fenced and unfenced sanctuaries. Grant Expenditure Grant Approved $12,000, expenditure $12,000 Field Team Equipment Rat Bait Specialist Monitoring Tracking Tunnels Action triggered cameras Rat Traps Total Total $12,000 Please find attached full details of grant expenditure. This grant allowed the Trust to safely and effectively clothe the field team who can walk up to 10ks per day, to cover costs of chainsaw and brush-cutter maintenance and running, to purchase rat bait, cameras, rat traps, and to have a contractor undertake specialist monitoring. Auckland Council Support for the Project Newsletters and presentations are the main way in which the Trust acknowledges our funders. The Trust has made fifteen presentations to a wide variety of individuals and organizations throughout 2013 and 14. Acknowledgements The Windy Hill field team!