Nature’s Corner — Early to Late Summer 2007–2008
Sitting on the Fence
Wellington green gecko on Karori Sanctuary fence © Tony Wills.
The Wellington green gecko (Naultinus elegans punctatus), having proved conclusively (see Return of the Native) that rumours of the possible extinction of the species in Karori are without substance, has continued to make occasional public appearances on the outside of Karori Sanctuary’s pest-proof fence. Sanctuary volunteer Tony Wills regularly walks the outer perimeter track, combining exercise and enjoyment of the outdoors with an interest in photography. On 1 February he met another Sanctuary volunteer, fence monitor Gill Mason who had just walked part of the perimeter with her dog to check that the fence was in good order. On seeing his camera, she directed him to where he might photograph a green gecko. It was apparently quite settled in its chosen spot as she had first observed it on her outward journey and had been surprised to see it still in the same spot when she later returned the same way.
Sure enough, the gecko was still there, basking in the late afternoon sun, when Tony arrived just after 5 pm. Initially it was about two thirds of the way up the fence, in the descent position (facing downwards). After a few camera shots it probably began to suspect Tony had predatory intentions, or perhaps it had simply had enough sun for the day, because it slowly turned and retreated upwards at a dignified pace to retire into the shade under the outwardly curved cap that tops the fence.
Sheltering under the Sanctuary fence capping © Tony Wills.
The fence cap is designed to keep climbing pest species like possums from invading the Sanctuary and has been totally effective in excluding them. Heaven forbid that geckos seen on the fence have left the Sanctuary for a bit of OFE (over-fence experience) only to discover on their return that, while it was a doddle to get out, the cap prevents them getting back in. If any animals can negotiate the cap barrier, it should be geckos. Minute hairs (called setae) form ridges under their toes and create an electrical attraction that gives them ‘sticky feet’ able to walk across or cling to surfaces other animals would just slide off. However, all geckos are not equal when it comes to stickability. Walking upside-down across the curved inside of a smooth metal cap to reach its outer edge, then somehow swinging out and up to get a footing on the upper surface seems a tall order for this tree-climbing specialist whose slender toes do not end in enlarged toe pads like some other species.
Captive green geckos sunbathing
If not stranded at the border, there is another possible reason for sitting on the fence. Sunbathing is not an optional luxury for lizards, but a necessity. They use the warmth of the sun to give them the body heat and energy they need for their muscles to work. Here are some of the captive green geckos in the cabinet at Round Lawn warming their undersides in the late afternoon sun. The boundary fence may appeal to wild geckos as a convenient vertical sun-bed because it elevates them above the grass and shrubbery to receive maximum sun exposure. The mesh provides a predator shield on one side at least, while still letting sun through, and they can hide under the capping if they feel threatened. They may even get food snacks delivered to them. Tony says he often sees insects on the fence – cicadas, moths, flies, weta and stick insects.
Over the Fence!
Wellington green gecko home at last?
Since writing the above, the gecko that Tony Wills photographed has crossed the fence with human help and is now a Sanctuary resident. Repeated sightings in the same vicinity aroused anxiety for its safety. On the outside of the fence it was accessible to climbing or jumping predators like the ship rat, stoats, and cats, as well as to anybody who did not know or care that it is illegal to remove a native lizard from the wild and might be tempted to catch it and take it home for a pet. There was also concern that the fence was impeding the natural movement of a protected species, interfering with its personal development perhaps by preventing it from moving on.
The transfer into the Sanctuary was made on 7 February when staff carrying out a regular maintenance check on the fence noticed the gecko exposing itself to danger again. It was lifted over to the other side and deposited in adjacent vegetation. The Department of Conservation has confirmed that it is permissible for lizards found on the fence to be placed inside if that is ‘facilitating their intended dispersal.’ So the way is open for more to apply for refuge by sitting on the fence. Hopefully none will be so foolish as to exhibit a desire to be ‘facilitated’ in the opposite direction.
Fair Weather Flowers
Group of three maikuku orchid plants
Maikuku / Common sun orchid (Thelymitra longifolia aggregate). When I walked up the Raingauge Spur Track on 9 December these little orchids were flowering on the margins of the track in several places. They were growing in hard clay, sometimes in small groups, sometimes just the odd one here and there. Each plant had a single leaf that trailed on the ground and a solitary flowering stem about 26-35 centimetres tall. The flowers, several to a stem, were about 18 millimetres in diameter.
Green growth and flowering is concentrated in spring and summer. During autumn and winter potato-like tubers lie dormant in the ground, waiting to sprout forth again when spring returns. The tubers are edible and in the past were sometimes harvested by Maori when food supplies were scarce in winter. However this is not a sustainable use. Andrew Crowe, writing in A field guide to the native edible plants of New Zealand (Reed, 1997) cautions that tubers should only be taken for food ‘in a survival situation’ because digging them up ‘destroys the orchid colony for years to come.’
Maikuku flowers
Most of us would say the flower has six petals, but a botanist would tell you there are three petals, and three sepals that resemble petals. When the flower is in bud or closed, the sepals form the outer protective layer, covering the true petals. At a standing glance the flowers appeared white, but when I knelt down and took a photograph at close range I found that on the plant I had selected, although the three petals still appeared white, the three sepals had a pinkish tint. I don’t know if that is typical of the whole population though.
It was fortunate the day was bright and sunny otherwise I probably would have passed by these orchids without noticing them. Sun orchids are so-called because they open their flowers in the sun but close them on dull days and at night. With their flowers closed they merge into the surrounding greenery and virtually disappear from view.
Animal or Vegetable?
Tunga rere / Huhu beetle © Allison Buchan.
Tunga rere / Huhu beetle (Prionoplus reticularis). This is the giant among our many species of longhorn beetles and also the largest and heaviest New Zealand beetle over all species. They fly about rather noisily on fine summer nights. They only have two weeks to live as an adult beetle and their priority is mating. This is such an all-consuming passion that they don’t eat, but having spent most of their former life (2-3 years) as a grub that does nothing else but eat, they probably don’t suffer food cravings during their brief adulthood. They can still give a nip in self-defence though. They also squeak, which seems to be a ‘let me go or you’ll be sorry’ sort of threat.
After mating, the females lay their eggs under the bark on dead branches and fallen trees. Native conifers like rimu, kahikatea and matai were once favoured, but they have readily adapted to introduced pines like Pinus radiata which is the prime choice currently available in the Karori Sanctuary. After the beetles expire, their genetic inheritance will live on in the new generation that will hatch from their eggs. Huhu is one of several Maori names for the stout cream-coloured grub that is the larval stage, although English speakers have adopted that name for the adult beetle as well.
Tunga rere / Huhu beetle © Allison Buchan.
The tunga rere in these photographs was about 4 centimetres long, measured from the front of its head to the tip of the wing cases. (Some may be up to 5 centimetres long.) Its segmented, jointed, antennae exceeded its body length. Longhorn beetles are so-called because they have long antennae. Their bodies usually have a furry covering. Note the brown fur visible on the head and upper body.
The paired dark brown wing cases (protective coverings for the flight wings beneath) are attractively ornamented with paler tracery something like veining on a leaf. It makes me recall an occasion when an American visitor handed me a single wing case and asked for the name of the plant that produced such an interesting seed case. My explanation that it was a wing case of New Zealand’s largest beetle was met with disbelief. He assured me that he knew a great deal about plants and there could be no doubt that we were looking at one half of a seedpod that had split open to shed its seeds. Although I suggested that he consult Andrew Crowe’s Life-size guide to insects at the Visitor Centre, I suspect he never did, because as he walked away with his find, he reiterated his firm belief in its vegetative origins. I imagine it reposing in a souvenir cabinet somewhere, labelled ‘seedpod of unidentified New Zealand plant’.
Two Summer Transformations
Tui feeding on wharariki flowers
Wharariki / Coastal and Mountain Flax (Phormium cookianum). In early December wharariki were still in flower and tui were revelling in the generous supply of nectar. Korimako / bellbirds and hihi were also in for a share whenever they could evade those tui claiming proprietary rights. This tui was climbing around on a korari (flax flower stem) at the junction of Lake Road and Valley View Track, leaving no nectar-bearing flower unplumbed. Of course the plants aren’t feeding birds out of kindness. The copious amount of orange pollen plastered on the forehead indicates they are getting their flowers pollinated in the process. What a cunning plan.
Unripe wharariki seedpods
After a prolonged absence, I passed by the same spot at the beginning of February and saw the abundant fruits of the pollination. Wharariki bears distinctive drooping seedpods that are bright yellowish-green when unripe. You will not see pods like this on its relative the taller harakeke / swamp flax. Not only do harakeke pods stand erect on a korari, they are never bright green.
Ripe wharariki seedpods
One korari was way ahead of the others. Its seedpods had ripened to darkest brown, nearly black, and twisted round in corkscrew fashion. The dried out pods had split three ways and when the korari was shaken, flaky, shiny, black seeds spilled out in dribs and drabs. The lightweight seeds are designed for wind dispersal. The twisting of the pods seems to help them retain seed until agitated by the wind. Because the pods hang downwards, if they just split open in the ordinary way, they could waste a lot of seed by dumping it all at once within or close by the parent plant on a still day. Twisting pods are characteristic of wharariki. Harakeke pods, because they are erect instead of dangling, don’t need to resort to twisting to keep their seed for a windy day.
Tainoka flowers
Tainoka / Makaka / New Zealand broom (Carmichaelia australis). Our local native broom was just coming into bloom when these flowers were photographed on a bush growing beside the entrance to the boat ramp at the southern end of Roto Kawau, the lower lake. It was 8 December and only two clusters were open but many more green flower buds were visible. In comparison to the yellow flowers of the introduced common broom (Cytisus scoparius), tainoka flowers are tiny, individually only about 5 millimetres across. There are quite a few of these brooms dotted about along Lake Road north of the Weka Fence and some smaller more recently planted ones among the flaxes on the west side towards the top of the sloping track that links the road to the Keith Taylor Wetland.
Unripe tainoka seedpods
When next seen in early February there was ample evidence of a bumper crop of flowers in the many green seedpods that had replaced them. The pods are very small, usually less than 10 millimetres long. Unlike those of common broom, you must look closely to notice them. Towards the end of February they were turning from green to brown. In autumn or winter they will open in a very unusual way. To find out how, look at ‘Throw seeds? Not Me’ in the Early to Late Winter 2007 edition in our Archive.
Road Rage
Female pepe parariki sips panakenake nectar © Allison Buchan.
Pepe parariki / Common copper butterflies (Lycaena salustius complex) are out and about in late summer looking for flower nectar, propositioning prospective mates, or sunbathing. I saw all these things happening when in the Karori Sanctuary on 6 and 13 February, but my most intriguing observation was made on 17 February while walking on Lake Road south of Tui Terrace. In a partly shaded area, two butterflies made a zigzag flight across the road in front of me, one in hot pursuit of the other. The pursuer was a little (34 millimetre wingspan) orange pepe parariki and the pursued was a larger (45 millimetre wingspan) kahukowhai / yellow admiral (Bassaris itea). I was intrigued. Was it a case of falling in love with someone of a different species?
Back across the road came the pepe parariki, alone this time, but I lost sight of it as it landed. When they close their wings, the bright orange suddenly vanishes. I was still trying to pinpoint it when the kahukowhai reappeared, landed in a patch of sunlight and spread its wings. Suddenly the chase was on again. I was witnessing a territorial dispute about a prime spot for sunbathing rather than unrequited passion. After the whole scenario had been played out for a third time, the bigger butterfly gave up and the smaller one was left in undisputed possession. The outcome was a complete reversal of what I would have expected from the apparently unequal contestants, but proves boldness and persistence can outweigh size at times.
Taking Flight
Raupo seed dispersal
Raupo / Bulrush (Typha orientalis). Our winter 2007 edition reported the unplanned establishment of raupo on the southern shore of Roto Kawau, our lower lake. It had arrived by natural means, and grew unnoticed among the sedges at the water’s edge until it flowered for the first time in 2007. With minimal alteration in appearance, the two tall flower heads had become seed-heads by the time their stems and leaves turned brown in winter. They remained in place as new green leaves sprouted and grew up around them in the spring. To my surprise the velvety brown seed-sausages were still there in December and showing no sign of breaking up. I began to wonder if they really did contain viable seeds. Could there have been a failure in the fertilization process? But apparently more time to ripen was all that was required. As February began the united front was disintegrating and seeds, teased free by the breeze, were parachuting away on tufts of down.
Have a Demon Grasshopper, My Dear
Conservation scientist Raewyn Empson and helpers
Here’s Mum handing out tasty picnic treats to the little ones, right? Wrong! This is not a picnic. And it’s not the Wild Foods Festival either. Conservation scientist Raewyn Empson is supervising the release of some more wetapunga o Raukawa Moana / Cook Strait giant weta (Deinacrida rugosa) into Karori Sanctuary. To give members and visitors an opportunity to see these super-sized insects of the night, 14 from a consignment of 86 were released in public as the culmination of a ‘meet the species’ afternoon at Tui Terrace on 17 February.
After special adult guests had released the first few, Raewyn invited children present to literally ‘lend a hand’ and there was no shortage of eager volunteers. One by one each child willingly stretched out a hand for Raewyn to place a wetapunga / giant weta on the palm. Sanctuary educator Tom Lynch or a parent recorded the thrilling moment on camera. Then under Raewyn’s careful guidance the child’s hand was lowered to the ground and the huge insect walked off to find a dark hiding place among the flax and toetoe where it could sleep until nightfall. One had other ideas but was soon apprehended and turned around.
'Oops, it's going the wrong way'
This is the second of four releases planned. For an account of the first release, refer to ‘Quite a Handful’ in the Mid Summer to Early Autumn 2007 edition in our Archive. On both occasions Matiu / Somes Island has been the source, but to promote genetic diversity, next time it will probably be Mana Island. The aim is to re-establish a sustainable population on the mainland, something that will only be possible in an environment like the Sanctuary where there are no rats and other predatory mammals.
Female wetapunga with radio transmitter
Some of the new arrivals were equipped with tiny radio transmitters that allow them to be located again. Since their release our conservation staff and other researchers have been checking daily on the position each has reached after its overnight wanderings. To find out how this is done, go to the Early to Late Autumn 2007 edition in our Archive and read ‘Keeping Track of Demon Grasshoppers’.
Which Poroporo?
Poroporo (Solanum laciniatum and Solanum aviculare). These two closely related Solanum species share the same common name. That is because the differences between them, if they were observed at all, seemed unimportant to Maori and (unless they were botanists) to Pakeha. In the past both species were valued primarily for their fruit (edible only when fully ripe) and as that was so similar as to be practically identical, most people saw no need to make a distinction. This remains true today. Most of us just lump them both under one common name.
Poroporo (Solanum laciniatum) flower
However, if you have a botanical bent and want to be able to distinguish the species, you can compare the two in the Sanctuary. This is best done during spring or summer, when both species are in bloom, because the main distinguishing feature is the form of the flower. Together, the petals of a flower make up its corolla. If the petals are not separate entities, but part of a continuous corolla, they are called corolla lobes. Solanum laciniatum is the commonest in the Sanctuary. Its flowers are blue-purple, about 3.5 centimetres in diameter, and the corolla lobes are blunt and notched in the centre.
Poroporo (Solanum aviculare) flower © Chris Moore.
Recently the opening of the new pontoon walkway brought a specimen of the other poroporo into view. It was spotted during January by volunteer guide Chris Moore who took this beautiful flower portrait. Solanum aviculare has smaller flowers, about 2.5 centimetres across. The flower colour is paler, varying from lavender to white, and the corolla lobes are pointed. When you are descending from the platform on Lake Road to the pontoon, pause on the seventh step of the second flight of stairs and look to the right. That shrub growing by the trunk of a macrocarpa tree is Solanum aviculare.
Korimako Chronicle
Korimako looking for wharariki nectar Photo by Tom Lynch.
On 5 February the fledging of chicks from the last nest being monitored effectively marked the end of the latest korimako / bellbird (Anthornis melanura) breeding season in the Karori Sanctuary. Conservation officer Matt Robertson, who organised the monitoring programme and maintains an overview of the status of our small korimako population, thinks it unlikely that any more nesting would have taken place since then because most of the pairs have had four clutches and adult birds are now moulting.
A total of six pairs bred in the Sanctuary this season, resulting in some 35 fledglings. Matt was especially pleased that, as he had hoped, more than just the two ‘Kapiti brides’ reported in our previous edition had settled in the Sanctuary. By November there were known to be four in residence. Their recruitment ‘provided a significant boost to the vulnerable population at the Sanctuary,’ he says, adding that they ‘settled quickly and got on with the job.’ All have fledged chicks. However, Matt cautions that ‘the survival of females and female fledglings through the winter months, and their subsequent recruitment next season will be the true measure of the successes we have had so far this season.’
Spine City: Enter at Own Risk
Kurikuri in flower near top of Eastern Firebreak
Kurikuri / Taramea / Speargrass / Spaniard (Aciphylla squarrosa). This was the sight that greeted me as I approached the top of the Eastern Firebreak while walking part of the inner perimeter track in early December. It looks a bit like an invading army and these plants would certainly inflict multiple wounds on anyone who had the misfortune to stumble into their serried ranks. Excepting the first one, the names above all warn that these plants carry weapons. ‘Tara’ is a Maori word applied to various sharp-pointed objects – a spear, a spine, a thorn. ‘Spaniard’ is thought to be a corruption of ‘poniard’, a type of dagger. ‘Aciphylla’ translates from Greek as ‘needle-leaved’. Those common names, Maori and English, are not limited to Aciphylla squarrosa but shared with several other rather similar Aciphylla species, all of which have dense tufts of narrow leaves that are spine-tipped.
‘Kurikuri’ differs in being a specific Maori name for Aciphylla squarrosa, although confusingly the same name is used for certain beetles that emit a bad smell as a method of self-defence. Considering kurikuri was one of the speargrasses formerly used by Maori as the source of a fragrant gum used to make perfume, I wonder if the name originated as a joke.
Male kurikuri flowers in November
There were a few kurikuri speargrasses surviving in the Sanctuary when the fence went up in 1999 but since that time this and two other kurikuri plantations have been established using almost 200 nursery-raised plants. The site pictured was the first to be planted so is the most advanced. A few of the plants flowered for the first time in November 2006, but nearly every plant flowered in November 2007. Like many New Zealand plants, Aciphylla species flower abundantly in certain years and poorly in others; they are also dioecious (having male flowers and female flowers on separate plants).
Female kurikuri forming fruit
Kurikuri flowers are tiny but they are concentrated on large flower stems that tower above the leaf tufts. They are protected, like the leaves, with an array of spines. Male flowers produce the pollen to fertilize the flowers of female plants. Once the pollen has been shed, the male flower stems have fulfilled their function. They collapse and decay.
The flower stems on female plants have more to do. They remain erect until they have ripened and shed seed. In this picture, taken in early December, you see a portion of a female stem with fruit developing. Seeds were starting to fall in late January when Matu Booth, one of our conservation officers, came to weed the site.
Periodic weeding is necessary, Matu explains, because kurikuri is ‘a transitional species that would normally give way to flax, barberry, gorse and manuka.’ By removing the competitors and making it easier for any seed produced to germinate, kurikuri is encouraged to become the dominant species. Piercing jabs from the ungrateful plants are an occupational hazard and he looks forward to the time when ‘sheer density’ ensures that only minimal maintenance is required to keep the plantations permanent and self-sustaining.
Potential condominiums for speargrass weevils
Who wants dense swards of such fiercely spiny plants? The critically threatened Wellington speargrass weevil (Lyperobius huttoni) does. Once the habitat this species needs has been recreated, its reintroduction and recovery will be possible. The weevils are totally dependent on Aciphylla squarrosa for food, shelter, protection from predators (those bristling spines are a deterrent) and completion of their life cycle. They need a reasonably extensive colony to sustain them because their larvae feed on the taproots, eventually killing their host plants. If there are too few, the weevils will be homeless and hungry in a few years, but if there are lots, natural regeneration from seed will be able to keep ahead of their demands. The denser the plantation becomes, the safer it will be for the weevils because they are most vulnerable to predation when crossing gaps between plants. When Spine City is completed, it will be their dream home!
Quail, Quail
Ever since 2006, when one or two pairs selected breeding territories in the lower valley, California quail (Callipepla californica) families have become a regular feature of the spring and summer months in the Sanctuary. The sight of Mum and Dad escorting their chicks on family food-foraging expeditions charms visitors who encounter them from time to time on Lake Road, the Union Mine Track and at Tui Terrace. Provided you don’t crowd them, or startle them with sudden movements or loud noises, they will tolerate your presence as they go about their activities.
California quail family outing
This family was photographed in early December on Lake Road. I think there were 8 chicks, but it was impossible to get an accurate count because they were zipping about and constantly appearing from, and disappearing into, the roadside vegetation where their stripy brown bodies gave them perfect camouflage. Out in the open they seemed to speed across the ground as if they were on tiny motorised wheels instead of legs.
The parents are assiduous in keeping an eye out for predators and call a warning to take cover if they think there is danger. Although the perimeter fence excludes mammalian predators like rats, stoats, or cats, they still have to be on guard against avian predators. These include the resident flightless weka as well as karearea / falcons and kahu / harriers that make occasional aerial hunting forays. However the presence of another predator was revealed recently, a reptilian one.
Tuatara enjoying his food. Photo by Tom Lynch.
On 9 February some visitors reported that while walking on the Union Mine Track they stopped to watch a family of quails. They were admiring the chicks, which were trailing along in the wake of their parents, when suddenly, as they came alongside a log, a tuatara reared up and ate one! This is not, I think, a danger any Californian quail parent could be expected to anticipate or detect. The two species have probably never lived in close proximity before and tuatara are masters when it comes to impersonating inanimate objects like rocks or sticks. It’s enough to make a quail quail.
The tuatara in the photograph looks quite capable of eating a quail chick, but is actually consuming a weta, which is a more usual item of prey. They are not fussy eaters though. Invertebrate or vertebrate, it’s all the same to them. If it moves and comes within reach, it’s on the menu. On Stephens Island, whence our tuatara came, they are known to eat the occasional fairy prion (Pachyptila turtur) chick. When a fresh, ready-to-eat, chicken dinner puts itself on your plate, so to speak, you can’t blame a tuatara for making a meal of it.
An earlier article about quails moving into Karori Sanctuary, ‘Californian Couple Opts for Karori Lifestyle Block’, can be found in the Late Spring to Early Summer 2006 edition in our Archive.