Nature’s Corner – Early to Mid Spring 2006
Kowhai Time
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| Kaka laps kowhai nectar Photo by Tom Lynch |
The first kowhai (Sophora microphylla) trees to flower at the Karori Wildlife Sanctuary this spring were young ones planted at the car park and either side of the Lake Road toilet block. Three were flowering by 9 September, and others soon followed, all no doubt benefiting from their location at the northern end of the Sanctuary in open, sunny situations where warmth is radiated from nearby tarseal or gravel surfaces. Two or three flowered for the very first time; others had their first flowers the previous spring. Big old trees that pre-date Sanctuary stewardship grow further south. Flowering in the vicinity of the Upper Dam started from mid September but most of the kowhai beside the eastern Round the Lake Track waited until the beginning of October.
The bright yellow flowers are an invitation to nectar feeding birds, but when there is competition among species, it is the heavyweights - tui and kaka - that dominate. The tui usually chase off any smaller birds they notice poaching in ‘their tree’ but tend to ignore kaka, perhaps having learnt discretion from earlier encounters. However I am told that the tables are sometimes turned. Others have seen a tui bully a kaka out of a kowhai tree. I suspect it would be a young kaka, lacking in experience and confidence. Whenever I have been watching, there have been several kaka in the one tree, so they definitely had the balance of power on their side.
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| Singing tui in kowhai tree |
Sometimes I see kaka feeding very delicately and seeming not to damage the flowers, but at other times flowers are ripped apart. Are they freeloaders, I wonder, or do they contribute to kowhai pollination? The tree entices birds with nectar for that very purpose, but it can’t screen out those that take the payment and fail to deliver the service. Tui are reliable pollinators. They and the kowhai probably evolved together. This tui has paused in its feeding and fluffed out its feathers to make itself look more impressive while proclaiming its territorial rights in song. The way the light catches the feathers reveals their iridescent colours. Note the kowhai pollen adhering to the feathers at the base of the beak. That is how it is transferred between flowers as the tui feeds.
No, not a kowhai
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| Teline flowering along Lake Road |
Montpellier broom (Teline species or hybrid). If you walk along Lake Road in spring you will see and smell the abundant bright yellow flowers of this shrub, which grows here and there along the roadside between Alison Morton’s memorial and the first Weta Hotel. The scent reminds me of eau de cologne and can be quite strong on a warm day. Foreign visitors occasionally assume they are seeing kowhai. I hate to disillusion them, but at least I can say that both belong to the same botanical family, the pea family (Fabaceae).
The three Teline species that grow wild in various parts of New Zealand are all introduced. They are native to the Mediterranean and to the Azores, Canary and Madeira islands. However, according to Colin Webb, writing in the book Wildflower City, the precise identity of what is commonly called Montpellier broom in our area is a bit of a mystery. He suggests that it is probably a hybrid, although ‘one parent must be Teline stenopetala’.
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| Teline flowers at close range |
There is a tale that a Karori doctor, whose leisure activities included gardening and walking, may have been the originator of the local wild population. He, if I recall the story correctly, would fill his pockets with seed from bushes in his garden, and during his walks would broadcast it in weedy or barren roadside areas with the idea of beautifying unsightly places. This, if true, is old history, perhaps relating to the days when the road cuttings were new and raw or when Appleton Park was a gully used as a rubbish dump. No current Karori doctors are implicated!
One day Teline will be gone from the Sanctuary, replaced by the native vegetation that is being restored. It is not much of a threat to native species, so its removal is not a priority. Like common broom and gorse (other members of the pea family), it adds nitrogen to the soil and acts as shelter to native seedlings that will eventually grow up though it and suppress it. It is not shade tolerant so does not persist under, or invade, native bush. In open areas with permanently low vegetation it may eventually need to be removed by hand. At present more pernicious weeds are being targeted, such as wandering willie (Tradescantia fluminensis) which is notorious for blanketing the ground and smothering native seedlings.
Keeping Kaka Sweet
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| North Island kaka Photo by Tom Lynch |
Among the Karori Wildlife Sanctuary’s many volunteer groups that give trust members the opportunity to contribute directly to our conservation projects is one called Kaka Avi-aiders that services the supplementary feeding stations provided for our North Island kaka (Nestor meridionalis septentrionalis) population. The stations are very sophisticated bird tables where kaka have access to a supply of dry food-pellets, specially formulated for parrots, and a beverage made from brown sugar and water that can substitute for natural foods like flower nectar and honeydew. Our flora restoration is still in the early stages and it will be a long time before we have a mature forest with the full range of species necessary to provide a constant and complete kaka menu.
Kaka avi-aiding work is done in pairs according to a pre-arranged roster. Individuals commit to one or two avi-aiding duties a month and the supplies are delivered whatever the weather. They have all become experts at dressing for the prevailing conditions, which can be many and varied. But they tell me they enjoy experiencing the Sanctuary in all its moods and that each tour of duty is different. You never know quite what you will see each time you set out to walk up the Lake Road and back via Te Mahanga Track. It might be a weka scooting across the road in front of you, trees that have come into flower since your last visit, or a close encounter with a kaka that calls in for a prepared snack when you are right beside the feeding station.
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| Lower Valley avi-aiding buggy |
Here is the unique Lower Valley avi-aiding buggy about to leave the Ops Shed loaded with the necessary supplies and equipment. It was purpose-built by volunteers Bob Cameron and Richard Northmore, members of a Wednesday Work Group that carries out many handyman tasks for the Sanctuary. The plastic containers at the front hold the food-pellets; bottles of sugar-water are stowed at the back. Plastic buckets are for collecting waste and stowing dirty equipment. Note the gumboots. It was a very wet day and overflowing creeks were flooding across the road in places.
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| Mother and daughter kaka avi-aiding team |
A tour of duty, including the preparation and concluding wash-up, takes about two hours. Maintaining hygiene and keeping records are important aspects of a kaka avi-aider’s job. The amounts of food and beverage being taken to each feeder are recorded before setting out. Similarly, any leftovers at a feeder are measured and recorded before being taken away for disposal. This is to build a picture of the extent to which kaka rely on the supplementary feeding and track seasonal changes in supplementary food consumption. If consumption falls or rises at particular times of the year, the amounts provided can be adjusted accordingly. In the picture the avi-aiders are about to replenish a feeding station. The avi-aider on the right holds the replacement bottle of sugar-water, a plastic jug to measure any unused sugar-water, and the recording folder.
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| Kaka using the food box |
The feeding stations have been especially designed to ensure the intended recipients are the primary beneficiaries of this food aid. Pellets are put in metal boxes with lids that open when a kaka perches on a lever that is also the convenient place to stand while taking food from the box. The lever is calibrated so that it cannot be depressed by birds of lesser weight than kaka. When, say, a blackbird perches on the lever to try its luck, the box remains shut. If some super-intelligent blackbirds ever figure out that two or three of them perching on the lever together will open the lunchbox, it will be back to the drawing-board. As competition rather than co-operation characterises their food-gathering behaviour, such an innovation on their part is unlikely. However, a few have developed the dash in, quick snatch and away routine to perfection and, when a kaka opens the box, can carry out this manoeuvre in a twinkling.
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| Kaka drinking sugar-water Photo by Tom Lynch |
The sugar-water is in bottles with nozzles that will dispense the liquid as long as a valve is opened by upward pressure. Kaka can do this with their beaks but so can other nectar-loving birds and screening them out has been a little more complicated. An early design had lids that it was thought only parrots would be able to open, but tui figured out a way they could do this that involved precision flying to grab the edge of the lid, force it down and perch on it to hold it open. Now the height of the nozzle above the platform is the screening mechanism, but still the odd tui has surprised us with unexpected elasticity in stretching up to break the height barrier. Recently, however, with so much nectar on offer from spring flowers like kotukutuku / tree fuchsia and kowhai there has been little incentive to poach.
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| Kaka looking for a late supper |
Use of the feeding stations fluctuates. They are restocked daily between 1 pm and 2 pm but that doesn’t necessarily mean that kaka will be lined up waiting for their avi-aiders to arrive. When there is plenty of natural food, they prefer to be out gathering their own in the bush and sometimes in people’s gardens. What they harvest for themselves is fresher, tastier, and in greater variety. The menu at the feeding station is familiar, bland and unexciting in comparison, but it does give security. If the day’s food foraging wasn’t as successful as expected, no one has to go hungry. Anyone still feeling peckish can drop in at a feeding station for a top-up before going to roost.
A secure food supply is important in persuading birds to settle and breed in the Sanctuary, in keeping the population healthy, and in helping parents keep all chicks in a clutch fed. Our supplementary feeding stations are also convenient places for monitoring kaka health, relationships, and behaviour, and for visitors to see kaka at relatively close range.
Marshalling Insects
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| Tutukiwi (Pterostylis banksii) |
Tutukiwi / Greenhood / Elfhood (Pterostylis banksii and related species). These little orchids have been flowering along both sides of the upper Beech Track, between V transect and the white ribbon marked HH N6, throughout October. They resort to force to ensure they are cross-pollinated. ‘When an opportunity arrives, give it a shove in the right direction’, seems to be the principle. A tutukiwi flower is arranged so that an insect landing on the lip petal (labellum) triggers a sudden movement. The insect is thrown down inside the flower and blocked from exiting as it came in. To get out again the insect has to follow a route that takes it over the stigma, which collects any other tutukiwi’s pollen it may be carrying, past a gland that anoints it with a sticky substance, and past the anther where its sticky body picks up the orchid’s own pollen. A very efficient pollen exchange has been accomplished. If the insect had been allowed to wander undirected, it might have transferred the orchid’s own pollen from its anther to its stigma, a sort of incest the orchid needs to avoid for the sake of its offspring. Fortunately, the insects don’t seem to resent their treatment and are not deterred from visiting other tutukiwi flowers and going through the same process.
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| Tutukiwi (Pterostylis banksii) |
Tutukiwi means ‘standing kiwi’ and you can see in the first picture that the flower is shaped like a little green and white kiwi, with a long pink beak, that has been caught in a noose. It doesn’t stay in the noose though, because those slender extrusions representing the noose later extend at right angles to the body. I’m not sure how one interprets that! The kiwi has sprouted long skinny wings? Perhaps it injured its beak in flying practice.
What's That on the Track?
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| Windfallen kotukutuku flowers |
Kotukutuku / Tree fuchsia (Fuchsia excorticata). These trees are fully clad in their spring foliage but are continuing to flower. They also have both unripe and ripe fruit from earlier flowers. Once flowers are pollinated they have fulfilled their function and no longer need to bribe birds. They cease nectar production, redden and then fall, making way for the developing fruit. During October, strong wind gusts have sometimes brought down fresh as well as spent flowers. These two, picked up on a Te Mahanga Track boardwalk, show the marked colour difference between a flower that has nectar and one that has not. The red flower has left a fruit behind, but the green and purple flower has the part that might have become a fruit still attached. It had not even started shedding pollen from its anthers when it was snapped off. Its yellow stigma collected some pollen from the flower picked up with it, but it’s too late.
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| Windfallen porokaiwhiri fruit |
Porokaiwhiri / Pigeonwood (Hedycarya arborea). Bunches of unripe porokaiwhiri fruit were also snapped off. These landed on one of our trackside bench seats. Porokaiwhiri is dioecious, so if you see a tree with fruit, you know it is a female tree. Notice how the fruits are attached to a small central disc by very short stout stalks. That feature can help you identify wind-blown fruit. To see a female tree with plenty of fruit still attached, go to the eel pool near the Henderson Lawn and inspect the dark-leafed tree across the track from the water pipes.
Small But Perfect
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| Hangehange flowers (enlarged) |
Hangehange (Geniostoma ligustrifolium var. ligustrifolium). When botanists say a flower is perfect, they don’t mean it is beautiful, they mean it has all the basic parts: a calyx of sepals, a corolla of petals, and male and female organs that are fully functional. Hangehange flowers qualify in all respects. Each flower has a pollen-collecting stigma (female) at the centre and out beyond that a circle of five or six stubby stamens (male). Those white dots between the hairy, greenish, petals are the pollen-bearing anthers atop the stamens. The flowers, which have been enlarged in the photo to show more detail, are small, about 7mm diameter. They are sweetly scented, but this seems to be only intermittently discernable. Hangehange has been flowering in the Sanctuary since about the last week in September and may be seen along all the tracks. By the end of October some bushes are scattering discarded corollas (the petals are all joined together, not attached separately) as they start forming seed capsules. The caterpillar? It was just passing through and did not eat any flowers.
Prickly Customer is Sometimes Pretty
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| Tataramoa flowers |
Tataramoa / Taramoa / Bush Lawyer (Rubus cissoides). If you notice that the bush track ahead is sprinkled confetti-style with small white petals, there will be a tataramoa vine flowering somewhere up above in the trees. They seem to have flowered exceptionally well this October. This huge swag of flowers was suspended above the steep Beech Track in mid October, but it has since disintegrated in the wind and rain. The small white flowers are from 1 cm to 1.5 cm across and, especially when newly opened, may be tinged with a slight flush of pink. They are pollinated by insects, which are attracted by their whiteness and their perfume. The flower panicles are devoid of thorns, but beware of the foliage and branchlets. The Maori name (both long and short version) means ‘climbing thorn’ and without those clutching thorns, that enable it to cling on to its neighbours and scramble up through them, it would not be able to climb up and claim a place in the sun.
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| Male tataramoa flowers, close-up |
Venerable old vines develop quite thick woody stems distinguished by occasional corky swellings. Towards the top of the steep Beech Track, one has been propped up to keep it clear of the track. It may look dead, but there is life at the far end, high in the crown of a large hinau, where it has flowered prolifically. If you turn right on emerging at the top of the steep Beech Track, you see the stem of another old vine slanting across the upper Beech Track and up into a tree. This too was flowering abundantly in mid October and being virtually above the track is much easier to view than the one in the hinau. Arching sprays of flowers have also been visible from Lake Road, especially looking down the bank near the south end of the mesh safety fence and in trees opposite post 26 or behind post 30 of the Research Area fence.
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| Female tataramoa flowers, close-up |
If there are still flowers around, use your binoculars to see if you can tell which are male-flowered and which are female-flowered vines. (Yes, this is yet another dioecious species.) Male flowers have white to cream-coloured stamens; female flowers have a green-coloured boss in the centre that on close examination turns out to be a mass of bulbous green ovaries, each topped by a white or cream stigma. It is easy to see how this boss, once fertilized with pollen, will grow into a raspberry-shaped fruit. The structure is all there.
For more about flowers and fruit in the Sanctuary during October and November refer to the Mid to Late Spring 2005 flora edition in our Archive.
Tieke Times Update
Our previous edition reported a tieke / North Island saddleback (Philesturnus carunculatus rufusater) taking bark from a Weta Hotel for nest-building purposes.
This was WM-WB and she built her nest in a pile of brush on the ground, just two metres from Lake Road. There she laid, incubated, and hatched her two eggs, aided by her mate RM-RB who brought food for her and the chicks. Both chicks fledged and there have been sightings of them with their parents along Te Mahanga Track. If this nest had been outside the Sanctuary it would almost certainly have been predated. A propensity for nesting close to the ground makes tieke easy targets for predatory mammals that hunt by smell.
Little Korimako Battler
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| Korimako / Bellbird Photo by Tom Lynch |
The gender imbalance in our small korimako / bellbird (Anthornis melanura) population has become extreme. Thirteen males have been identified in the Sanctuary but only one female. It seems that harassment from excess unattached males may have driven away the other females that were present last year. This little battler is the only one to re-bond with her mate from the previous season. Since late August she has built three different nests, all within about 15 metres of each other, but was only confirmed to be incubating eggs on 17 October. She had been observed building the current nest six days earlier. She and her mate have been under constant pressure from the other males and that may have disrupted or delayed her egg-laying. I do hope she can confound the neighbours from hell this time. She deserves to succeed.
Cruising Kahu Causes Panic
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| Incubating kawaupaka Photo by Tom Lynch |
Just south of Alison Morton’s memorial, there is currently a small notice on the side of Lake Road to indicate two kawaupaka / little shag (Phalacrocorax melanoleucos) nests that can be glimpsed in a tarata tree. Pausing here on 14 October, I could see a bird sitting on the lower nest as usual, but the upper nest was deserted. Enquiry revealed that kawaupaka nesting had been disrupted by a visit from a kahu / Australasian harrier (Circus approximans) that had recently spent a couple of days scouting the area. The kawaupaka were apprehensive that their nest sites were being eyed up as future fast-food providers. Kahu are known more as scavengers than hunters, so birds on the wing are not at much risk from them, but a helpless chick in an exposed nest would be a tempting takeaway. Repeated passes by this large bird of prey caused incubating birds to panic as they felt very vulnerable to an attack from above while sitting on their nests. Whether any landings were made at nest sites or any direct attacks made on sitting birds or chicks is not known but of seventeen kawaupaka nests in various trees either side of the lower lake, twelve were abandoned as a result of this safety scare.
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| Kawaupaka drying off Photo by Tom Lynch |
The kahu has since moved on and at least eight kawaupaka pairs have built new nests. The potential predator and potential prey are both native birds and their interaction is part of the natural ecology of the area. Meanwhile, life goes on. When next I stopped by the sign on Lake Road I could see a large chick moving about in the lower nest while a parent stood guard. It is now starring in its own reality show on a nearby video monitor. At the upper nest I was intrigued to see two adults conversing in low tones. The previous owners discussing possible refurbishment or just a temporary place to rest and dry the feathers? The only way to find out is to take a look when next you pass by.
This edition of Nature's Corner was written by Sanctuary volunteer Allison Buchan on 23-24 & 28-29 October 2006. Information relating to tieke, korimako, the kahu visitation and kawaupaka nesting statistics was provided by Sanctuary conservation staff. Thanks to the Kaka Avi-aiders for answering questions and taking me on a tour of duty. Photographs are taken by Allison Buchan, except where otherwise indicated, and are © Karori Wildlife Sanctuary. Clicking on photos with blue borders will take you to a larger photo.
Published 4 November, 2006.