Aotea/Great Barrier Natural Environment-Islands Monthly Update December & January
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Aotea/Great Barrier Natural Environment-Islands monthly update December & January Prepared for the Great Barrier Local Board 28/01/2020 Aotea Great Barrier Local Board funded programmes Argentine ant & Plague skink surveillance • Rosalie bay Rd – Because of the connectivity with the Mulberry Grove Argentine ant site, sites at top of road were monitored with nothing detected. • A selection of sites between Okiwi airfield and Orama were monitored with neither Argentine ants nor Plague skinks detected. Okiwi Community Pest Coordinator • Rat trapping is continuing, cat trapping will resume in February. • The coordinator is in the process of doing a door to door visit with people revisiting priorities for the project given a number have dropped out of rat trapping. The survey completed in 2017 will be revisited as a prompt, however the visits will be more focused as an opportunity to chat face to face with individuals about where they see the project going. • The results will be available in March 2020. • feedback to date indicates a desire to continue with community led bird counts in addition to the island wide counts, to continue rat trapping on public land, to put more emphasis on rat monitoring than recording every capture on all private land (many are using rat bait or a combo of traps and rat bait). Pest Pathways • Pest pathway ambassadors attended training with Conservation Advisors in December. • Key message: Buy Locally - This message covers three aspects of environmental protection, waste minimisation, low carbon and biosecurity. By reducing freight to Aotea visitors can reduce their carbon footprint and reduce the risk of inadvertently transporting pest species. • Ambassadors will be advocating the use of local nurseries and providing information on biosecurity programs e.g. feral cat control, argentine ant eradication and provide information on the species present and absent on Aotea. • Ambassadors were present at Shoal Bay Wharf, Claris Airport and Port FitzRoy wharf periodically during the Christmas new year period. Rabbit Control • A Scope of Works has been finalized for the Local Board funded rabbit control occurring in March, this work has been contracted to Glen Coulston of Goodwood Aotearoa Ltd. and will include night shoots in Kaitoke, Claris, Okiwi and Orama. • Pre-control spotlight counts are planned for the last two weeks of February. Pest prevention Norway rat surveillance • Norway rats are not known to be established on Aotea. Norway rat surveillance occurs annually at key entry and exit points on Aotea to confirm the absence of this species. • Norway rat surveillance occurred in January using Victor professional rat traps, these traps are larger and more robust than the commonly used Snap-E or T-Rex traps primarily used to catch ship/roof rats on Aotea. Victor trap at Port FitzRoy Doc 200 Port FitzRoy • The traps are checked weekly over January to ensure rats are not too decomposed to identify. See identification tips below for ship rats/roof rats (Rattus rattus) and the absent Norway Rat (Rattus Norvegicus) Stoat sighting • On Tuesday 25th December - DOC Okiwi received a phone message reporting a potential Stoat sighting on Oruawharo lane, Medlands. The message was not picked up due to the closure of the DOC office. • The informant later informed the Oruawharo Medlands Ecovision Group of the sighting (date unknown) who informed Auckland Council on the 30th of December 2019 at 2.38pm. Auckland Council contacted the informant by 3.12pm and recorded an interview. • The Informant had witnessed an animal crossing his property in a loping fashion, the animal then disappeared behind a Pohutukawa tree. The sighting occurred on the 25th December at approximately 10am. • After interviewing the informant Auckland Council were not convinced that this was not a genuine sighting. However, due to the seven-day delay between the sighting and the report it was decided a detection dog would not be immediately deployed. • A decision was made to deploy a trap network of DOC200s within the proximity of the sighting. Should further reports come in or any sign of stoat presence observed a stoat detection dog would be deployed immediately. Doc200 trap Network deployed in Medlands Great Barrier Island Pest Animal Programs Feral Cats • Feral cat control has been on hold for the last two months due to expected poor catch rates at the peak of summer. Feral cat trapping is forecast to resume in March. Broken Islands-Rodent control • Contractors have installed further rodent management stations on Opakau Island with the intension of managing increasing rat numbers on this islet. Argentine & Darwin’s ants • Only one (Sugarloaf) of the 12 sites has yet to receive a first round of monitoring. • 60,042 pottles have been deployed (across all sites) in this first round. Of these, 66 returned with Target ants (Argentine or Darwin’s) at a percentage of 0.1. • Comparatively, the percentage of target ants found after round 1 of the 2018/2019 season was 1.57% (see table 1.0 below) Table 1.0 Monitoring totals and target ant detections across all sites – Round 1 Site Total Total % of # of pottles % of Target % of Target Tubes Pottles pottles with Target ants ants from used deployed returned ants 2019/20 2018/19 empty (Round 1) (Round 1) Oceanview RD 16 15,384 8.75 4 0.03 0.45 Sandhills Rd 8.4 8290 0.8 4 0.05 0.02 Gray Rd 10 9755 11 18 0.2 11 Blind bay Rd 1 553 9.8 0 0 0.4 Mason Rd 5 2615 20 0 0 0.46 Thomas Rd* 1.5 1923 3 7 0.4 1.24 Okupu 4.5 3598 7 6 0.16 0.12 44 Medland Rd 6.5 6435 2.5 19 0.3 0.09 Puriri Bay Rd* 1.2 1149 1.5 2 0.4 3.7 Sugarloaf TBC TBC 1.03 Mohunga 2 741 4 2 0.3 0.5 (Darwin’s) Mulberry Grove 10 9599 16.7 4 0.04 0 Totals 66.1 60,042 6.6 66 0.1 1.57 • Small infestations discovered within the Mulberry Grove and Sandhills sites (after the previous season had no detections). This is typical when reducing high densities over a large area where it can become difficult to detect nests of this size when only visiting a site once in a season. • A secondary round of monitoring has been added to operations to increase the likelihood of detection of such small infestations and assist in auditing round 1 operations. Plague skinks • Between October and December Insect Sticky Traps (used to catch skinks) were active for 40 nights in all five trial cells. Three adult plague skinks were caught in trial cell 6 (2nd trap only cell), this was the only cell where plague skink captures were recorded. • This concludes the first round of trapping to determine plague skink extinction in each cell. Trapping will resume in cell 6 over January and February to increase the likelihood of plague skink extinction. Trapping will be rested in the four remaining cells until March when the second round of 40 nights trapping will commence. • Between October and December thirteen native skinks were trapped in trial cell two (1st trap only cell) this was comprised of eleven ornate skink and two copper skinks. Four native skinks were trapped in trial cell 6 (second trap only cell) which included one moko, one copper and two ornate skinks. One ornate skink was trapped in trial cell 8 (low density chook cell). • No skinks were trapped in cell seven (high density chook cell) or cell one (pilot chicken cell) during the first round of trapping. See summary table of skink captures below. • A small fence breach in cell two was reported on the 6th January and fixed the same day. The cause was attributed to high winds. It is possible this breach was open for one week over the contractor’s holiday break. Figure 1: Location of trial Cells GBI # of Trap Skinks detected Grid/Line Dates # of traps nights nights 7th - 10/10/19, 11 Ornate 21st - 25/10/19 2 copper 12th-30/11/19 Cell 2 (1st trap 1st-16/12/19 only cell) 512 40 20,480 7th - 10/10/19, 3 plague skinks 21st - 25/10/19 1 moko skink 1 copper 12th-30/11/19 2 ornate Cell 6 (2nd trap 1st-16/12/19 only cell) 292 40 11,680 7th - 10/10/19, 21st - 25/10/19 Cell 1 (CC1 pilot 12th-30/11/19 chicken cell) 294 40 11,760 1st-16/12/19 7th - 10/10/19, 21st - 25/10/19 12th-30/11/19 Cell 7 (CC3 high 1st-16/12/19 density chook cell) 115 40 4600 7th - 10/10/19, 1 Ornate skink 21st - 25/10/19 12th-30/11/19 Cell 8 (CC2 low 1st-16/12/19 density chook cell) 150 40 6000 3 plague skinks 14 Ornate skinks 3 copper skinks Round one totals 54,520 1 moko skink Great Barrier Island Pest Plant Programmes Strategic Weed initiative (SWI) • Bushy Asparagus – Claris site completed, and NO target plants found • Kahilli Ginger – Puriri Bay Road (ongoing) • Kahilli Ginger – Okupu (ongoing) Some access issues with new landowner, contractor to discuss program and report back if access is not granted. Boneseed was identified within this site with approx. 15 plants in total found. One of which was mature and in seed. • Kahili Ginger/Boneseed – Palmers Lookout (ongoing) • Moth plant – Fitzroy site (1st visit completed) report on finds pending Total Control Weeds • Royal fern – Golf club & Okiwi site completed, report on finds pending • Japanese Honeysuckle – Rosalie Bay site (1st visit completed) report on finds pending • Asparagus Umbellatus – Roaslie Bay site completed, and NO plants found • Pennywort - Claris Landfill site completed, and NO plants found Juvenile kahili ginger (puriri Bay Road) Juvenile Boneseed (Okupu foreshore) Weed surveillance • The Weed surveillance program continued with a concentrated effort within the Tryphena area.