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Nature’s Corner — Mid to Late Spring 2007
Pretty in Pink
Makomako / Wineberry (Aristotelia serrata) is flowering in late October and early November. It is another New Zealand species that is dioecious (having male and female flowers on separate trees). These photographs show how male and female makomako flowers differ. They have been enlarged so they can be seen in detail.
The actual flowers are only 4-6 millimetres in diameter but we notice them because they are not scattered singly but displayed many at a time on clusters of branching stems. This makes it easy for insect pollinators to find them.
The flowers often appear pink from a distance but if you examine them closely there can be quite a colour range with individual flowers varying from creamy-white, to pink, to crimson. Some trees have much paler flowers than others, although the petals do tend to acquire more colouring as they age.
The flowers face downwards, like tiny cup-shaped bells with scalloped rims. To find out whether they are male or female you need to look up inside them. Male flowers are packed with pollen-producing stamens. Those pictured above belong to the male tree growing on the west side of Lake Road as you come to Birdsong Gully.
Across the road and beside the first seat in the Birdsong Loop is the female makomako where the second picture was taken. The main interior features of the female flower are a round green ovary surmounted by a pink 3 or 4-lobed stigma that is there to collect pollen. A pollen grain contains sperm to fertilize the ovary so it can become fruit. Makomako fruits resemble tiny currants. When they ripen in summer, birds are very prompt in harvesting them.
Makomako is quite common in the Sanctuary and you will pass other specimens as you continue up Lake Road. You can even look for makomako flowers when walking across the Upper Dam because, towards the western end, trees of both sexes grow on the south side of the dam wall.
Tieke Times
Tieke / North Island saddlebacks (Philesturnus carunculatus rufusater) have been doing so well that intensive monitoring was suspended after their fourth breeding season in Karori Sanctuary. However, it is expected to resume next season when a student will be undertaking some research on the population. In the interim, volunteer Helen Griffiths is coming in once a week to monitor tieke breeding activity in part of the western side of the valley. She has identified seven pairs with territories in that area and has been observing three nests.
Photo by Tom Lynch.
The first nest was seen at the end of August. It was in a man-made nest-box and already contained two eggs. These hatched on 8-9 September and fledged on 4 October. The other two nests were in natural sites and these are obviously much more difficult to find.
It can take hours of patient observation and tracking a bird’s flight paths to pinpoint exactly where the nest is concealed. Sometimes, although you repeatedly follow a bird with your eyes, each time it just seems to vanish in an instant and you still can‘t figure out how or where.
One nest was hidden within a pile of dead branches. It has produced one fledgling. The other was tucked right inside a small hollow log lying on the ground. That nest contains two chicks that will probably fledge about 5 November. ‘To check on them,’ Helen says, ‘I just about have to stand on my head.‘
Helen knows there are or have been other active nests in her monitoring area. She has seen the male of one pair carrying food and on 25 October she watched another pair feeding three fledglings. They were hopping around and flying very competently and she thinks they had probably been out of the nest for about two weeks.
Helen describes the female parent of three as a ‘fantastic mother’. One season she fledged chicks from a remarkable four clutches. She is actually one of the ‘founding mothers’ of our tieke population, having been part of the original 2002 reintroduction, and Helen has monitored her breeding for four out of six seasons, so regards her as rather special. Helen can distinguish her call from those of other tieke as she has a distinctive dialect. Her original mate disappeared before the last breeding season. It is thought he probably died of old age. Her new mate is a ‘young fellow’ that was hatched in the Sanctuary during the 2004-2005 breeding season.
Postscript: Second-clutch nesting is underway. The ‘fantastic mother’ has already built a second nest. Helen discovered it in a nest-box on 31 October and thinks she might see some eggs on her next visit. It is beautifully lined with silky scales plucked from new ponga or mamaku fronds.
Spring Scents
© Allison Buchan.
Rangiora / Bushman’s friend (Brachyglottis repanda). This has been one of the most noticeable of the October-flowering trees and shrubs because of the way huge numbers of tiny florets are massed together in creamy-white fluffy clouds. If you put your nose in one of these clouds, there is a delicate smell of honey. I don‘t know if this beetle is one of the insect pollinators that the scent attracts, but it has perfect camouflage for such a role.
Hangehange (Geniostoma ligustrifolium). Many paired clusters of tiny green flowers occur at intervals along the slender branches but they are often not easily seen among the leaves. The flowers can give off a sweet musky scent, but it is very elusive. Often I can‘t smell it at all. Hangehange is very common along Lake Road and all the bush tracks. Flowering was at its peak in mid October.
Kohuhu (Pittosporum tenuifolium). The sweet scent of the dark reddish-purple flowers of kohuhu is a favourite with me, but it only becomes discernable when the light is fading at the end of the day. The pollinators that respond to the scent signal are said to be night-flying insects, presumably moths. Individual kohuhu along Lake Road have flowered at various times during October but the season is drawing to a close. However, as the month ended, there were still two kohuhu with flowers in the vicinity of Heritage Lawn — a tall female among the trees along the channel fence on the south side of the lawn and, on the opposite side of the channel, a shrubby male on the left of the track some five paces east of the old pohutukawa.
Tarata / Lemonwood (Pittosporum eugenioides). The lemon-coloured flowers do not have a matching lemon scent; they are honey-scented. When a tree is in full bloom the scent can be quite overpowering, especially on warm evenings. Nearly all of the young tarata along Lake Road flowered this October, probably for only the first or second time in most cases. They are adults now and can be expected to flower annually in future. Sadly the flowers don‘t last very long. I think that tiny green seed capsules might be replacing them before this is published. But check the tree on the north side of Round Lawn and the tall one at the south exit from Alison Morton’s memorial. They tend to be late flowerers. And remember, whether the honey-scented flowers are present or not, tarata does have a permanent source of lemon fragrance in its resin and its leaves.
Ti kouka / Cabbage tree (Cordyline australis). Sheathed bud spikes were appearing above the leaves on several trees at Round Lawn, Birdsong Gully and the Keith Taylor Wetland in late October. Each one contains thousands of developing flowers that should be out on display later in November. Their fragrance attracts many insect pollinators to come and sip their nectar.
Porokaiwhiri / Pigeonwood (Hedycarya arborea). Flower buds were just starting to open on some trees as October ended. This is a dioecious species so some trees will have male flowers and others will have female flowers. The starry male flowers pictured are about 1 centimetre in diameter and have a pleasing lemony perfume. In the centre of each one are lots of pollen-producing stamens. One of the first male porokaiwhiri to flower along Lake Road is usually one just south of WX transect on the west side of the road. A little further along on the same side is a female tree that is identified with a sign.
Montpellier broom (Teline species or hybrid). If a scent like eau de cologne wafts over you when walking on Lake Road, this is what it will be. For more about this exotic weed, refer to the Early to Mid Spring 2006 edition in our Archive.
Hihi Herald
Photo by Tom Lynch.
Hihi / Stitchbirds (Notiomystis cincta) in the Karori Sanctuary expect all mod cons when it comes to choosing a nest site. The founders of our population came from Tiritiri Matangi Island where man-made nest-boxes were the norm and they and their descendants have no intention of lowering their standards. This greatly simplifies monitoring because there is no mystery about where to look for nests. A preliminary check of nest-boxes on 10 September revealed that males had already begun putting twigs inside, possibly as a sign of ownership.
Thirteen breeding pairs are being monitored. At the end of October there were four nests with eggs hatching successfully and one nest where hatchlings had died. Ron Goudswaard, who co-ordinates the monitoring, says ‘For the first time we have twice as many males as females, and males other than the mate are going into boxes and disturbing the female incubating.’ This is a concern, but Ron adds that most eggs are hatching successfully despite the interruptions.
Daytime Kiwi-Spotting?
During October-November you can hone your powers of observation and enliven your bush walks by taking up this pastime. No, I‘m not referring to feathered kiwi, but to little green orchids called Tutukiwi / Greenhoods / Elfhoods (Pterostylis banksii and related species) that loiter on the margins of tracks in mid to late spring. Tutukiwi means ‘standing kiwi’. Look for them along the upper Beech Track from about V transect down to the next corner, which is where this photograph was taken on 20 October.
The flowers were just emerging then and yet to develop a proper kiwi-like shape. With their beaks still pointing skyward, they looked more like standing bitterns than standing kiwi. There may be the odd one to be spotted towards the top of the steep branch of the Beech Track too.
Other places where tutukiwi usually appear are the western section of the Round the Lake Track between the OSNZ F8 sign and the junction with the Faultline Track, the upper Faultline Track in the vicinity of bait station 54, upper Valley View Track before and after Best Mother’s seat, and the Turbine Track above the Tui Glen junction.
To find out more about tutukiwi behaviour read ‘Marshalling Insects’ in the Early to Mid Spring 2006 edition in our Archive.
Not a Native
Cherry laurel (Prunus laurocerasus). Each year I usually get presented with one or two sprigs of this and asked for the name. People are rightly puzzled by its presence in bush bordering the eastern section of the Round the Lake Track between U and TU transects. Because of the glossy and leathery dark green leaves these trees are often assumed to be karaka (Corynocarpus laevigatus), until the flowers appear and prompt a rethink.
Cherry laurel is a native of Europe and Asia. Despite its laurel-like foliage, it is a member of the well-known Prunus genus, which includes cherries, apricots, almonds, peaches and plums. Like them it was brought to New Zealand in the early days of European settlement, but unlike them it was not brought as a source of edible fruit or to grace the garden with impressive displays of spring blossom, but for its hardy, decorative, evergreen leaves and dense growth habit which made it a useful hedging plant.
It has gone wild in several parts of New Zealand, including the Wellington district. The small ovoid fruits ripen through red to purple black and are eaten by birds that spread the seeds in their droppings. However, I think the cherry laurels beside our Round the Lake Track were probably planted there many years ago, as they seem to form a row. One day they will be replaced by genuine natives — kaikomako, perhaps, for the korimako / bellbirds, or tawa for the kereru — there are lots of possibilities.
How are the Whiteheads?
Photo by Tom Lynch.
The Karori Sanctuary population of popokotea / upokotea / whiteheads (Mohoua albicilla) had not been monitored since the 2002-2003 breeding season but is being resurveyed currently. The original translocated birds had been banded before they were released in the Sanctuary, but their nests proved very difficult to locate during the earlier research work and were usually inaccessible anyway, so most of the existing population is without identifying leg-bands.
How is a researcher to know if there have been sightings of several different birds or multiple sightings of one bird? ‘The solution,’ explains Matu Booth, ‘has been to select areas and map the whitehead territories within these using GPS [Global Positioning System technology]. The idea is to identify male territories as an insight into population density and habitat usage.‘
On 22 October the first sighting of fledglings from the current breeding season was made on Lake Road opposite the Kaka Amphitheatre just south of Tui Terrace. ‘They make their presence known by their characteristic buzzing begging sounds as they fly after their parents,’ Matu says. He calculates that the eggs from which these fledglings hatched were laid about mid September.
Kawakawa on the Menu
Kawakawa (Macropiper excelsus) are putting on new leaves to replace those ravaged by previous generations of kawakawa looper moth (Cleora scriptaria) caterpillars. It seems to have been a good year for this moth because I have seen many examples of once heart-shaped leaves stripped until little apart from the radiating ribs remain. Such extreme consumption is usually patchy, affecting only certain branchlets where perhaps several moths happened to deposit their eggs, or maybe an exceptionally fecund ‘mother of the nation’ moth. The remainder of the foliage may be damaged, but to lesser degrees, leaving the shrub or tree with enough leaf-surface to photosynthesise food for survival.
As kawakawa has apparently withstood plundering by these little herbivores for hundreds of years, a balance has presumably evolved. It cannot be in the moths’ interest to wipe out an important food source their caterpillars depend on. However, there are places where defoliation has been so severe that I wonder if the balance has been tipped. It is especially noticeable where kawakawa is growing under exotic pines alongside the Valley View Track in DD transect.
© Allison Buchan.
I have yet to find a kawakawa looper actually on a kawakawa leaf although I have tried from time to time. They are quite tiny, green-coloured, and cling to the underside of leaves to do their eating, so they are invisible most of the time. All those I have captured have been detected in the act of abseiling from a kawakawa bush by silken thread. This is their method of direct travel to another destination and also a way of escape when disturbed. I have arrested the descent of several during October with a strategically placed hand, so it seems a new generation is already active. If you then put the caterpillar on a kawakawa leaf, it doesn‘t linger on the upper surface but rapidly takes refuge on the underside, allowing observation of its looping method of locomotion as it flees.
This one was about 6 millimetres in length. You may be able to see that it has legs on the front segments and others (called prolegs) on the rear segments but none in between. The caterpillar stands on its prolegs and extends the rest of its body forward, using its front legs when they come in contact with the surface to advance to full stretch. Then it draws up its rear end, resulting in the central portion being forced up into a loop.
Those White Patches on the Scarp
In late October isolated trees with white flowers are standing out from the surrounding green of the bush canopy on the western scarp. These are heketara (Olearia rani). Like some of our other trees, heketara tend to flower heavily one year, sparsely in succeeding years, then profusely again. This looks like a good flowering year.
Heketara is one of the tree daisies. The individual daisies are relatively small, only about 1 centimetre across, but being borne in clusters makes them more conspicuous. Where the Valley View Track runs beside the Research Area fence, you can take a closer look at a heketara at post 301.
Korimako Chronicle
We have four breeding pairs of korimako / bellbirds (Anthornis melanura) this season, which may seem low but is twice as many as last season. The first nest of the season was located on 16 August. It belonged to one of the two females that bred in the Karori Sanctuary last season. She has abandoned her mate of the two previous seasons in favour of a much younger male who only hatched last season. Matt Robertson says that the ex-husband is ‘alive and well in adjoining territory but has not paired up.‘
Our previous edition told of the capture on Kapiti Island of ten females that were then released in the Sanctuary. It seems they have been less than impressed by the male talent on offer here. Nevertheless, Matt is delighted that two were brave enough to accept a mate from our catalogue of ‘badly-behaved bachelors’ and hopes that a few more pairings might yet be discovered. All the prospective brides have a pale blue band above a metal band on either the right or left leg. Very appropriate, come to think of it, to have them wearing blue garters.
Korimako / bellbird translocations often fail, so two out of ten electing to stay and breed is still a plus. These females are very important additions to our fragile population because none of last season’s female fledglings appear to have been recruited as breeding adults. Unfortunately, two makes little impression on the overall sex ratio imbalance, so the problem persists of an excess of unattached males harassing the few females in the population. But the good news is that so far seven korimako chicks have fledged and there are three active second clutch nests. On 25 October eggs were being incubated in two of these and three chicks were being brooded in the third.
Photo by Tom Lynch.
The supplementary feeding stations on Te Mahanga Track, on the lower Beech, Swamp and Round the Lake tracks, and in the Discovery Area, are all hotspots for sighting korimako just now. When I visited the Discovery Area on 25 October, a very forward korimako fledgling, who had fully mastered the art of flying, was guarding feeding station 15 in between bouts of heavy drinking. (Nothing stronger than sugar-water, I assure you). Any hihi that approached was promptly chased away by this precocious little chap, the son of a ‘Kapiti bride’ and an ex-bachelor. I hope he is not on a sugar-fuelled rush to ‘badly-behaved bachelorhood‘, and that we will have a suitable match for him when the time comes.
Great Leaves, Shame about the Flowers
The puka / akapuka (Griselinea lucida) that grows on the old pohutukawa tree has come of age. This spring it has its first flowers. But don‘t expect blooms in proportion to the leaves. I measured a leaf that was 19 x 14.5 centimetres, but a flower is only about 4 to 6 millimetres in diameter. You have to look carefully to notice them at all. Puka are dioecious so I was interested to find out if this one was male or female. Its flowers have stamens to produce pollen and they have petals, so now we know. It’s a male and there will be no fruit following the flowers on this puka. Female flowers are even more minimalist, lacking petals and stamens, but their ovaries have the potential to become fruit. To get to this puka, take the bridge across the overflow channel from the Heritage Lawn, turn left, and inspect the base of the pohutukawa.
Reptilian Ambassadors
These two chilled-out tuatara (Sphenodon punctatus) — one female and one male — briefly fulfilled ambassadorial roles for their species immediately following the powhiri and welcome that marked the arrival of 130 new recruits to the Sanctuary’s tuatara population on 19 October 2007. Safely held in expert hands, they appeared quite relaxed as eager admirers gathered to inspect them at close range, clicking cameras and asking tuatara-related questions of their bodyguards. Many took advantage of invitations to gently touch a tuatara on the back and feel their cool scaly skins. The sensation was something like touching beadwork or bubbled plastic. The scales are made of keratin, like our fingernails. Those who touched part of the serrated crest that traces the line of the backbone confirmed that the little peaks were pliant and incapable of defensive stabbing to fend off an aggressor. The tuatara seemed oblivious to the contact, but their heads, needless to say, were out-of-bounds to the touchers. Tuatara need to absorb heat from their environment to raise their body temperature and provide energy for their muscles, so they probably found the warmth of the hands holding them, combined with the warmth of the sun on their backs, made for quite a pleasant basking experience.
To touch a tuatara is a rare privilege and, unless necessary for authorised scientific research purposes, is only permitted at the Sanctuary on a few special occasions and under expert supervision. These are not touchy-feely New Age reptiles. Their ancestors co-existed with dinosaurs. So if you meet a tuatara on one of the Sanctuary tracks, the advice is: look but don‘t handle.
They are naturally solitary creatures, very territorial, and not amenable to casual petting. To a warmed-up tuatara, a groping human hand or tentative finger can only be one of two things: a dangerous attack or dinner. Either way, a bruising and bloody bite is a likely response. Docile and slow they may appear, but biting is something they can do quickly and unexpectedly if you mess with them. It’s releasing you that would be the slow part. The teeth on the lower jaw slide in like shears between two rows on the upper jaw. That arrangement of teeth is one of the characteristics that distinguish tuatara from lizards. It also gives a vice-like grip that cannot be prised open. You must wait in painful thrall until the tuatara thinks it’s safe to let you go, a decision that cannot be hurried.
As the pictures above show, an obvious difference between male and female tuatara is the size of their crests. The female has a very modest crest. The male’s is far more prominent and he uses it as part of his macho body language. During courtship or territorial disputes, he makes the peaks stick up more stiffly, giving himself a bigger, sharper-looking, profile. It’s a case of ‘crest to impress’.
More about the tuatara transfer in Tuatara transfer trebles mainland population.
This edition of Nature’s Corner was written by Karori Sanctuary volunteer Allison Buchan in late October 2007. The bird articles were based on information supplied by the following Karori Sanctuary conservation officers: Matu Booth (tieke and whitehead), Ron Goudswaard (hihi) and Matt Robertson (korimako). Volunteer bird-monitor Helen Griffiths was a major contributor of information for the tieke article. Thanks also to Frances Gazley for a korimako tip-off. Unless otherwise indicated, photographs are taken by Allison Buchan and are © Karori Wildlife Sanctuary. Clicking on photos will take you to a larger version.
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