Nature’s Corner – Early to Late Winter 2007

Marking Winter at the Wetland

Raupo in winter, Roto Kawau wetland

Raupo / Bulrush (Typha orientalis). Most New Zealand trees and plants are evergreen and provide few clues to the season. In the bush canopy at Karori Sanctuary only the deciduous kotukutuku / tree fuchsia (Fuchsia excorticata) and the deciduous pohuehue vine (Muehlenbeckia australis) make winter visible by blotching the expanse of green with the brown tracery of their bare branches and tangles of leafless rambling stems. Now we have a new seasonal indicator at the Roto Kawau wetland. Raupo has established itself on the southern margin of the lower lake. Its long green strap-shaped leaves die off as winter arrives but, bleached, dry and papery, continue to stand at the water’s edge, swaying and rustling when agitated by a breeze. Two long-stemmed seed-heads, the first to appear in the Sanctuary, accompany them. The seeds, packed together in a cylindrical mass, look like brown velvet sausages mounted on sticks.

‘Bleached, dry and papery’ raupo leaves

Each individual seed is furnished with a tuft of downy hairs to act as a parachute and help it float away on air currents or water when the ‘sausage’ eventually disintegrates. I am not aware of any nearby raupo colony that would be a source of seed and it is thought that the seeds from which these plants grew were probably flown in from a distance stuck to the feathers or feet of a duck. In the past, the down from seeds was harvested by Maori to be used like cottonwool when dressing wounds and sores and as a stuffing for pillows and poi. Bundles of raupo leaves were gathered for thatching roofs and both leaves and stems became wall lining when constructing whare.

Pateke dabbling in Keith Taylor wetland

I like this native reed-mace with its dramatic seed-heads but it can be invasive and take over small shallow wetlands. Hopefully our raupo can be managed so as to keep it confined between the lawn and Roto Kawau, which is mostly too deep to be extensively colonised. We don’t want it to choke up the Keith Taylor wetland across the way and leave no open water for the resident pateke / brown teal to dabble in.

Kiwi pukupuku / Little spotted kiwi © Peter Daniel

Courting Kiwi

Kiwi courtship in preparation for the new breeding season has commenced. The confirmation came on the night of 7 August when visitors on a guided nocturnal tour in the Karori Sanctuary were thrilled to receive a special glimpse into the life of the Kiwi pukupuku / Little spotted kiwi (Apteryx owenii). All the kiwi pukupuku in the Sanctuary are completely wild. They select their own territories within which they wander at will, defending their boundaries against encroachment by neighbouring kiwi and hunting their natural foods. No supplementary feeding occurs. It is usual to hear kiwi calling to each other on nocturnal tours. Seeing kiwi is serendipitous but the rate of sightings this winter has been very good. One nocturnal tour in July was especially fortunate to have 3 separate kiwi sightings! The courting couple were seen at the Lake Road entrance to the Morning Star Mine Track. Sanctuary conservation officer Matt Robertson, who was the tour guide, says ‘both birds were vocalising with grunts and snuffling. The male could be seen stroking the female’s back with his bill.’ The male could be incubating an egg (or two, though that is rare) by the end of the month, Matt estimates.

• More about kiwi pukupuku

Looking into Whauwhaupaku Flowers

Male whauwhaupaku flowers

Whauwhaupaku / Houhou / Five-finger (Pseudopanax arboreus). This is one of three tree species that flower and dispense nectar in the Karori Sanctuary through the winter months. Its flowers are designed for insect pollinators rather than birds, but nectar is a valuable commodity in winter and tui, korimako / bellbirds and hihi have all been seen licking nectar from the centres of male flowers at times. I expect they also snap up any incautious insects that are there for the same purpose. Blowflies are often prominent among the insect visitors. The flowers are so small (male flowers around 7 mm in diameter, females less) that it seems surprising that they can produce enough nectar to be of interest to birds. There must be something really special about the flavour or intensity of the nectar because the tui get very excited when these trees start coming into flower in late June. At least the flowers are concentrated together, on multiple starburst-shaped structures called compound umbels. This makes them much more visible to insects and birds than single flowers could be and means the nectar-feeding visitors can access a lot of flowers at once without burning up too much energy moving about in search of them.

Male whauwhaupaku flowers in detail

Whauwhaupaku are predominantly dioecious (having male and female flowers on separate plants). The petals of flowers of either sex are purple on the exterior surface and greenish-yellow on the interior surface. When in bud they are often mistaken for tiny purple fruits. Once the buds have opened we notice the pollen-producing flowers of male trees because of the conspicuous yellow-tipped stamens that project beyond the petals. These were photographed on 26 July on a tree at the south side of Heritage Lawn. Compare these flowers with the female flower below.

Female whauwhaupaku flower and flower buds

Unless you can get very close, it is a challenge to tell what a female tree is doing. From just an arm’s length away, buds, flowers or fruit all look much the same. As explained in our previous edition, the female flowers drop their petals soon after opening, which makes them scarcely recognisable as flowers, although they are still carrying on their function of attracting potential pollinators with minute amounts of nectar. In the picture, one female flower has been captured with petals still attached. Most of the others are in bud. The closed petals form a tiny dome at the top of the much larger fruit-like ovary, which is the most prominent feature of female whauwhaupaku flowers. You may be able to see that the petalled flower has stubby little stamens tucked right down against the base of the petals. These are not functional. No pollen is produced. When the petals fall off, those remnant stamens go with them. Female whauwhaupaku all seem to produce plenty of fruit after flowering, so obviously the insect delivery of pollen from male trees is effective. Whether the birds contribute anything is unclear, but they don’t seem to disrupt the process anyway. There is still a lot that is not fully known about the relationships between our native plants and animals.

Winter Butterflies

Kahukura on a kawakawa leaf, 23 June

Kahukura / Red admiral (Bassaris gonerilla gonerilla). These haven’t entirely deserted us during winter. On occasional sunny days when temperatures have warmed sufficiently to become almost springlike, the odd one has come out to investigate. Individuals have been spotted in zigzag flight above Lake Road and the Union Mine Track on such days and sunbathing on low vegetation at several locations along the inner perimeter track. Presumably they take the opportunity to fortify themselves with some flower nectar, although I have no observations confirming this. There is often gorse and Darwin’s barberry flowering in nearby places.

Where to look for Kotukutuku Flowers

Hermaphrodite kotukutuku flowers produce blue pollen

Kotukutuku / Tree fuchsia (Fuchsia excorticata). This is another of the nectar-dispensing trees that flower throughout winter. Kohekohe (Dysoxylum spectabile) is the third. You will find articles about kotukutuku flowers in the Early Winter 2005 flora edition and in the Winter to Early Spring 2006 edition in our Archive. Flowering continues through spring. A good place to view the flowers this season has been opposite the Kaka Amphitheatre, just south of Tui Terrace. Several young trees grow on the east side of Lake Road there and they offer an eye-level view of the buds and flowers. As there are both female and hermaphrodite trees among them, there is an opportunity to compare the two kinds of flower.

Fruits from the Underworld

Winter showers bring fungal fruit-bodies into view as they emerge into the atmosphere to bear and shed spores. Many are in shades of brown and pass unnoticed by human eye, but here are two colourful examples that I encountered during walks in July and early August.

Violet coral fungus

Violet coral fungus (Ramariopsis pulchella). This looks as though it belongs on some tropical coral reef, but in late July and early August several were visible on a bank on the eastern side of Te Mahanga Track, 15 paces south of Basic Bridge (no side railings) or 28 paces north of the Lake Road crossing. The branching, coral-like fruit-bodies are quite small but rather beautiful. This particular one was 2.5 cm tall and 4cm across. They are a vivid violet-purple when they first emerge from the soil but become paler as they age. The spores form on the surface of the branches. It will be interesting to see if these ‘corals’ reappear in the same spot next winter.

Red pouch fungus

Red pouch fungus (Weraroa erythrocephala). You might think that the cap is immature and yet to pull away from the stem and assume an umbrella shape, but this never happens. The pouch-like cap may grow in size but it has no spore-shedding gills requiring exposure so continues to embrace the top of the white stem. Inside, the red pouch is packed with a brown mass of spores. Pouch fungi are sometimes called tobacco-pouch fungi because the pouch full of brown spores reminded people of a pouch full of tobacco, such as smokers once carried to refill their pipes. Tobacco-pouches suitable for elves judging by the size. The largest I have seen in the Karori Sanctuary have pouches that are no more than 3cm in diameter and stems no longer than 3-4cm. The photograph was taken in late July beside the Totara Track (the southern extension to Te Mahanga Track). The pouch on the left has lost its stem and has broken open, exposing the spores. The break may be the result of natural decay, or the work of birds or invertebrates. Both are thought to have a role in dispersing the spores of pouch fungi. In mid August there was quite a colony of red pouch fungi about 7 paces south of the brush fence hide on the west side of the Keith Taylor Wetland Trail.

Throw Seeds? Not Me

Tainoka seeds hanging in there

Tainoka / Makaka / New Zealand broom (Carmichaelia australis). Our previous edition included a picture of the ripe seedpods and mentioned that, unlike the seedpods of the common introduced broom (Cytisus scoparius), these do not open explosively to broadcast their seeds. The way tainoka pods open is rather curious. The pods partially disintegrate. Both sides fall away, leaving only the marginal framework of the former pod, but the mottled seeds are still hanging in there, attached to the frame by slender threads. Perhaps they are waiting for spring? These were on a broom bush planted near bait station 24 on the west side of Lake Road as it approaches the Weka Fence from the north. The pods are small, usually less than 10 millimetres long, and may contain from one to six seeds but mostly have between two and four. Although the local population has mottled seeds, Carmichaelia australis is quite a variable species and there are populations in other parts of the country that have colourful orange-red seeds.

Kidnapping Korimako on Kapiti Island

A korimako / bellbird held safely and securely. Photo by Matt Robertson

Kidnapping? Well, korimako were captured and carried off without their consent! But be assured that the local iwi, Te Ati Awa ki Whakarongotai, had given approval and the Department of Conservation (DoC) had issued a permit for the operation. Ten female korimako / bellbirds (Anthornis melanura melanura) were to be relocated from Kapiti Island to Karori Sanctuary in an effort to correct the sex ratio imbalance that has developed in our small breeding population. Sanctuary conservation officer Matt Robertson took the lead role in planning and managing the capture and transfer, under the guidance of conservation scientist Raewyn Empson. Altogether, five Sanctuary conservation staff, two Department of Conservation employees and four Sanctuary volunteers made up the team that carried out the project. Matt describes them as ‘a most capable and committed bunch,’ who made his job easier than it first looked.

This article looks specifically at the mist-netting work of the Sanctuary volunteers, three of whom – Frances Gazley, Helen Griffiths and Ros Batcheler – were interviewed about their experiences on the expedition. Volunteers were selected for their existing bird-monitoring and bird-handling skills and their ability to work co-operatively in a team. All had a track record of previous involvement with bird-related volunteer work for the Sanctuary.

The Whare, with net poles packed in tubes stacked on the veranda © Frances Gazley

All food was repacked in plastic bins and everything being taken to the island went through a thorough check for pests at the Kapiti Boating Club before embarkation. The capture team landed on the island about 3pm on Saturday the 7th of July. On the ramp that extended from the front of the boat, a human chain was formed to unload equipment and supplies that the resident DoC ranger then conveyed by trailer to The Whare. This historic hut, containing two bunkrooms, is used by DoC to accommodate contractors or people engaged in scientific research.

After getting settled in and listening to an orientation talk, a start was made on setting up the mist nets at a variety of sites on Rangatira Flat in readiness for an early start the next day. Cords that would function as halyards or guy-ropes were attached to long, slender, aluminium poles. Where necessary some light pruning of trees, cutting of bracken and trampling of long grass was carried out at overgrown sites to make sufficient room for the nets and allow ease of movement when servicing them. The net length (12 or 9 metres) was paced out and a pole thrust into the ground at either end. To anchor and stabilize each pole, two guy-ropes separated by a 90-degree angle were tied off to nearby tree branches. Then it was time to extract the net from its bag. Two or three people usually assisted in putting a net into position, lifting it up and paying it out, supporting it on their shoulders and hands to prevent contact with the ground where it would pick up debris or get tangled in the vegetation. At either end of a net, there are loops at intervals along the vertical edges and these are tied to the halyards on the poles. The net can then be raised or lowered by pulling on the halyards. Two nets had been fully erected before fading light stopped work for the day and these were pushed up and tied in long sausage-like bundles, ready to be let down next morning. This must be done whenever nets are unattended, otherwise one would risk a harvest of feathered corpses.

8 July, a perfect day for mist netting Photo by Matt Robertson

The new day dawned frosty, calm and clear. Sky and sea turned blue in the sunshine and across on the mainland the snow-clad peaks of the Tararua Range sparkled on the horizon. It was just the sort of day to bring the birds out and to make manning the nets a pleasure rather than a feat of endurance. At 7.45am the two pre-erected nets were unbundled and lowered into position. One was in a flight path to a flowering whauwhaupaku / five-finger (Pseudopanax arboreus) as these are a magnet to nectar-eating birds in winter. In a very short time 3 female korimako had been caught. Meanwhile the rest of the nets had been raised and brought into operation. Sometimes two nets were erected adjacent to each other, both having one pole in common. Mist nets have a diamond-shaped mesh of fine black threads. Different gauges are used according to the size of the bird species being targeted. A 38mm mesh was used for the korimako. When the mist net is spread it is almost invisible against the background vegetation provided it is not in full sun. It is not stretched flat, but falls in several horizontal folds that run lengthwise. These are known as ‘pockets’. A very large bird like a kereru just bounces off a net of 38 mm mesh, but the smaller birds are entangled, trapped there until a net-monitor extracts them.

Male korimako, showing sharp hooked claw Photo by Matt Robertson

There was no division of labour at the nets. The volunteers were engaged in the same tasks as the staff members present and the roles of net-monitor and ‘runner’ were swapped around as occasion demanded. Net-monitors watched their nets from unobtrusive positions so as not to deter birds from using that flight path. The instant a bird hit the net they came to disentangle it. Everyone had a two-way radio to call for back-up help if more birds zapped into their net than they could handle. Separating bird and net was the trickiest part of the operation. You needed to be aware of the direction the bird had entered the net because it had to be extracted the same way. You needed to know how to hold the bird firmly but gently so that it kept still and was prevented from getting more entangled and from attacking you with beak and claws. A korimako has painfully sharp hooked claws that can easily penetrate a misplaced finger. Once control was gained, the bird was carefully disentangled from entrapping strands as quickly as possible so as to minimize stress.

Sanctuary conservation officers Rob Cross and Ron Goudswaard display the bird-bags Photo by Matt Robertson

All birds caught in a net were entered on the net data sheet. Time, the species, and its sex was recorded, also the name of the person who had taken it from the net. If a female korimako was caught, it was put into a black cotton bag, the drawstring closed and knotted, and a ‘runner’ called to take the bag to the temporary aviary where two Sanctuary staff members were examining, measuring and banding the prospective ‘brides’. Other birds were released. The by-catch included tui, kakariki, chaffinches, whiteheads and male korimako. Kakariki / Red-crowned parakeets were gorgeous to look at but ‘their heads swivel right round and they bite like hell, drawing blood.’ Tui have ‘needle-sharp skin-piercing claws.’ However both are larger than korimako and instead of getting stuck in the mesh, tend to tumble down into the fold (or pocket) below their impact point. By grasping the net above them and taking the slack out of the pocket they were in, it was often possible to tip them out without needing to take hold of them.

With Raewyn Empson’s guidance, Les Moran prepares a korimako for tarsal measurement Photo by Matt Robertson

Owing to the excellent conditions, by 11 am there were 12 females in the aviary and the netting operation, for which two days had been allowed, was already complete. The two extra birds were reserves in case any of the original ten were judged unfit for travel when the time for translocation came. After helping disassemble the nets and take equipment back to base, the volunteers were able to spend time observing and learning about the processes that had been applied in the aviary. Some training was given in measuring a bird’s tarsus (ankle) and in a ‘thigh-hold’ technique that is used when a bird has to be handed from one person to another for a procedure like banding. There was also free time to explore the island and watch and listen to the birds in their natural habitats until deteriorating weather impelled departure from the island the following day. A startling moment that is remembered fondly occurred during a Sunday night walk. Crossing a culvert suddenly triggered a cacophony of extraordinary shrieks and brays that came from underfoot. ‘We felt like the Billy Goats Gruff being addressed by the troll,’ laughs Helen. It was a thrill to think there were little blue penguins sheltering below and to spot one later in the bush.

Female korimako / bellbird: 'Will I or won't I?' © Peter Reese

All the volunteers felt it had been a privilege to participate in the korimako / bellbird capture and to stay on Kapiti Island. Some of the highlights mentioned were the opportunity to see many different native birds in intimate detail when removing them from the nets, getting to know staff members better and being able to share in their knowledge of birds, and being able to spend full days and nights on the island instead of the few hours of an ordinary day trip. There was also the satisfaction of contributing to the maintenance of the Karori Sanctuary korimako population.

The females they helped catch were released into the Sanctuary on 13th July. As yet they have been seldom seen but it is natural for them to be inconspicuous at this time of year. We are all hoping their presence will transform our ‘badly-behaved bachelors’ from rampant sexual predators into responsible parents. The staff and volunteers have done all they can to bring this about. They have delivered potential brides to the bachelors’ domain, now it’s over to them. Matt Robertson hopes to see some courtship occurring by the end of August.

Thwarting Weka Banditry

Kapiti Island weka: ‘People-watching is my hobby.’ Photo by Tom Lynch

During our ‘korimako kidnapping’ operation on Kapiti Island, weka (Gallirallus australis) skulked in the bushes, ready to snatch any opportunity for a meal that the human activity might offer. Wise to the predatory nature of these birds, those manning the nets took care that any bird caught low in the net did not sag down to a level that would expose it to a weka attack. Dangling netted birds were lifted up out of weka range while they were being extracted. A small bird temporarily disabled in a net would be grabbed by a weka if it got half a chance. Most likely it would be injured during a failed attempt to drag it from the net regardless of entanglement but if the weka succeeded in freeing it, the bird would be devoured. Constant vigilance ensured this never happened.

A Kapiti Island weka assesses a tourist’s backpack Photo by Tom Lynch

Nevertheless, one enterprising weka scored a gourmet meal by unzipping a pocket on a backpack and scarpering with a packet of scroggin. The backpack had been purposely put pocket-side down on the ground in order to prevent pilfering, but clearly this weka had a diploma in backpack geography and zipper management. While the owner was occupied in extracting a netted bird, it winkled its beak underneath the pack, grasped the tag on the zipper, and picked the pocket. A brief attempt at pursuit was abandoned almost as soon as it began. The culprit had vanished like a thief in the, er, bush. No doubt it had a lovely picnic in some secluded spot. The nuts and dried fruit would have gone down a treat, but the crystallized ginger?

The following day there was an attempted sandwich-snatch but the victim, with commendable sangfroid, refused to relax his grip and the leaping weka scored no more than a sliver of crust. Obviously this was a novice and no match for the Artful Dodger previously described. The shy and seemingly innocent weka that reside in Karori Sanctuary do not prepare one for the bold bandits of Kapiti Island.

This edition of Nature’s Corner was written by Karori Sanctuary volunteer Allison Buchan on 13-14 & 16-17 August 2007. The kiwi article draws on reports by Matt Robertson and Phillip Stuart. Thank you to Frances Gazley, Ros Batcheler and Helen Griffiths for sharing your Kapiti Island experiences and observations for the korimako and weka articles. Thanks also to Matt Robertson and Les Moran for additional details relating to the korimako capture and translocation and to Peter Reese for allowing me to see mist netting in practice. Unless otherwise indicated, photographs are taken by Allison Buchan and are © Karori Wildlife Sanctuary. Clicking on photos will take you to a larger version.