Right now in the Ark...
A view across the reservoir, looking into the new AW Block, installed urgently to provide predator control to the area chosen by the recently released kokako.
Although not visible in the above photograph, northern rata trees (metrosideros robusta) are starting to spread their crimson displays across the highest parts of the canopy - a welcome demonstration of their recovery from possum attack. Possum numbers were drastically and persistently reduced by Operation Forest Save in 1998, and continue to be controlled by Ark baiting.
The flowers and young leaves of rata, and its coastal cousin the pohutukawa, are so heavily browsed by possums that these giant trees are dying out in areas where possum predation is not controlled.
Northern rata starts as an epiphyte and turns into a tree; Southern rata is a tree only, while other members of the genus are vines throughout their life, but all enliven the bush with their brilliant flowers. Below is a picture of metrosideros carminea blooms:
Rodent baiting:
On Saturday 1 August the new season's baiting programme started. Old bait was removed (not that much ever remains from the previous season's nibbling), and a bag of fresh bait placed in each station. In October and November, the lines have been re-visited, and where bait has been taken a new bag placed. This reduces rat numbers down to very low levels, and allows birds and plants to have a successful spring breeding and seeding.
We have just completed the third phase, where just the peripheral 150m of bait stations are replenished all around the boundary of the Ark, to intercept invading rodents. Wasp numbers have now built up to a level where it is hazardous to continue to travel off-track, so no further baiting will be done until next season.
Check our baiting progress map, to see the most recent activity.
Trial of less intensive baiting:
As a trial of less intensive baiting, L and P Blocks are being baited as a 100 x100 grid ie only every second bait station is having bait inserted. Starting on 21 November, bait stations have started to be installed, also using this system, in the new AW block (in the area north of Cutty Grass track, currently favoured by the kokako). The current trial is an extension of the progressive reduction in bait quantities that has been in operation since the earliest days of the project. Ark rodent statistics make it clear that a 50 x 100 grid is highly effective, so now it is time to test whether a less intense pattern of bait placement will still achieve adequate clearance of predators.
Robin Monitoring:
Every year since the first release of 53 robins in 2005 Ark volunteers (with overseas students a key element) have sought out nest sites and monitored the breeding success of the pairs - typically three clutches of 2-3 chicks per season. The new release introduces the prospects of new pairs, and new nesting territories, so the call has gone out for more volunteers to spread out and find where the birds have settled. Andy Warneford has been put in charge of organising this activity, and anyone who is interested in helping should contact our Volunteer Coordinator (karen@colgan.co.nz) to be put in touch with him. Volunteers need to have time available Monday to Friday, and to be fit enough to move off-track through our steep and slippery bush.
Hihi monitoring:
Since the onset of Spring Andy Warneford and his team have been working to track down the nesting of the hihi. If you can commit to regular sessions, are fit enough to move quickly off-trail, or patient enough to lie still for hours observing nests, then Andy would like to hear from you.
Contact Andy at andywarneford@orcon.net.nz or 021 644 853
Rodent Monitoring:
On the weekend 27-28 November, volunteers laid detection papers in 109 tunnels in the Ark, and in 40 outside. The results once again confirmed the effectiveness of the Ark rodent control: outside the Ark the rate of tunnel visits was 53% rats and 25% mice, while inside the Ark it was just 0.9% rats and 5.5% mice.
These results follow immediately after completion of baiting, and demonstrate a very satisfactory suppression of rodent predator numbers.
Check out the graphs showing monitoring results [click here]
Meanwhile, the Stoaters continue to tramp around their circuits, and 71 mustelids have been caught in the year ending 30 June 2009 (check out the maps showing their results).
Then there's the team maintaining the hihi feeders, the weekend attacks on weeds, navigators extending lines to fill in gaps..
Kokako for the Ark:
Dept of Conservation ranger, Hazel Speed is shown above, at the moment of release. Kokako are back, after an absence of around 60 years! (Photograph courtesy of ARC)
Capture of these precious birds has to be carried out with great care, and in particular breeding pairs must be kept together. Add in the difficulty of positioning nets in the steep terrain, to catch birds that swoop between the top of giant trees, and capture becomes an unpredictable event, and release correspondingly become an ongoing and gradual process.
These difficulties meant that this season only six birds were able to be translocated, and only two of these were males. Thus, until another catching programme is carried out in Spring 2010, the population of kokako in the Waitakere Ranges must remain at a maximum of two breeding pairs.
The birds all have transmitters attached, and a dedicated team of volunteers have tracked their location over the weeks since release. This has shown that the birds explored widely in the Waitakere stream valley, including one lone female who spent a few days in the Forest and Bird Matuku Reserve. However, most of their time has been spent around and above the reservoir.
Accordingly, the Ark's plans to extend predator control into this area are being accelerated. A new block of bait lines has been navigated south-east of the reservoir, and bait stations are now being installed, to protect any nests that are formed this summer.
This new area will also function as a trial of a less concentrated pattern of bait station placement, with the stations situated 100m apart on each line.
Click here to enjoy the sight and sound of the kokako.