Arno Gasteiger

Bird Island

The spade brigade, as they were dubbed, platened 280,000 seedlings—a city of trees—into which a host of rare birds and reptiles were released. Within sight of New Zealand’s largest city. Tiritiri Matangi is now a template for island restoration and endangered species management.

Written by       Photographed by Arno Gasteiger

The island’s magic starts before anyone steps off the ferry: loud, ringing bird calls come from the wooded hillsides ahead. As visitors walk down the wharf, their eyes widen in delight at the unfamiliar sounds—this is what Joseph Banks must have meant when he wrote of the “melodious wild musick” of early New Zealand.

Avian antics  are a distraction as the crowd of 150 visitors to Tiritiri Ma­tangi gathers for a brief introduction by the DOC ranger. Unseen behind them, a kingfisher stands patiently on the wharf railing, holding a skink in its beak, waiting to feed its hungry youngsters which are growling softly from a hole in the nearby bank.

As small groups of people head off into the bush, the volume of sound increases. Birds are everywhere. Tui pour their hearts out from the trees overhead; tiny whiteheads flit across the track; dust-bathing quail are herd­ed like sheep up the track, until the silly brown balls of feathers have the sense to veer off into the undergrowth. Robins hop up to the group, waiting for the guide to clear away fallen leaves to expose insects and worms.

The bird calls reach a crescendo around a feeder where sugar water attracts bellbirds and stitchbirds. The sugar-hyped birds zip in and out of the feeder, seemingly oblivious to their observers.

The daily cargo of day-trippers from Auckland alights on Tiri’s dock. Among them are birdwatchers, school groups, tourists, DOC staff and a few volunteers to conduct the guided tours.
The daily cargo of day-trippers from Auckland alights on Tiri’s dock. Among them are birdwatchers, school groups, tourists, DOC staff and a few volunteers to conduct the guided tours.

A kereru flaps noisily overhead, its wings whistling. The brilliant green blur of a kakariki zooms down the track, and a kokako appears, walking towards the visitors. The large grey bird with bright blue wattles on its cheeks and a black mask around its eyes pauses, then, using its strong beak and legs, neatly climbs a nearby cab­bage tree. This, explains the guide, is Te Koha Waiata (The Gift Of Song), a particularly tame male. Spreading its stubby wings the big bird glides over the heads of the group, lands on the track, and continues its stroll. Shortly after, its haunting flute-like song carries across the valley, to be answered by a nearby mate.

Up at the lighthouse, at the end of their guided walk, the visitors are entertained by some of the island’s twelve takahe; large, portly, blue and green birds with enormous red beaks. There are less than 250 of these birds left in the world. They were thought extinct until 1948, yet on Tiri they stroll calmly around, grazing on the grass like sheep. Meanwhile, down at the beach, Greg, the boldest of the bunch, cheerfully fraternises with boaties, reaching into their lunch bags and strolling across picnic blankets checking for crumbs. Since Tiri is an open sanctuary (which may seem like an oxymoron) anyone can land there, and Hobbs Beach is a popular destina­tion for boaties. Feeding the birds is strictly forbidden, but Greg is adept at helping himself.

Some people disapprove of his behaviour, declaring it would be much better if Greg “behaved like a bird”. For a time he was banished to a remote bay, but soon found his way back to the beach. For most people, however, Greg epitomises Tiri, which was always intended to be a showcase for the birds.

We are not used to being included in nature in this way. Our urban birds such as the introduced blackbird and sparrow know to flee from humans. But, lacking any mammalian predators as they evolved, the trusting nature of New Zealand’s native birds has been their downfall. A robin or a kokako wouldn’t know a rat if it stared them in the face, nor do they know how to defend themselves against one. Fortu­nately they are safe on pest-free Tiri.

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The bold plan to replant a bare island, stock it with rare birds and open it to the public was conceived in the late 1970s by profes­sors John Craig and Neil Mitchell of the University of Auckland. The plan was championed and overseen by the Hauraki Gulf Maritime Park Board (HGMPB) in the 1980s until that organisation was absorbed into the newly-formed Department of Conservation. The respected conser­vationist Jim Holdaway, a founding HGMPB member, said at a recent DOC forum that the establishment of the open sanctuary at Tiri was the HGMPB’s greatest achievement: “It was the start of the movement. The thinking public has moved towards a recognition of the natural values and the ecology of this country, which we had better look after.”

Conservation was in vogue when planting began on Tiritiri Matangi in the 1980s, and many community and school groups were keen to get in­volved. For ten years, from 1984-94, hundreds of volunteers came to Tiri, usually in winter, which is good for tree-planting but rarely guarantees a smooth voyage—people often arrived green with sea-sickness.

Over the decade, the “Spade Bri­gade” as they were dubbed, planted 280,000 seedlings—a city of trees —and in the process sowed the seeds of one of our most successful conser­vation projects.

The Hauraki Gulf branch of For­est and Bird was the first community group to plant trees on Tiri, in a trip organised by Mike Lee, now chair­man of Auckland Regional Council. “It poured with rain, which certainly gave the trees a good start,” he recalls. “Each group was allocated a block of land, and for years we planted trees in ‘Waiheke Valley’. I went out and checked on it in 1995—they’re all in lines!” This was an unforeseen side-effect of the initial planting method in which people lined up on top of a ridge and marched downhill, planting as they went. Since each person had selected a different species, Tiri got some striped hillsides. “But the trees don’t care, the birds don’t care, and it’s nothing that a chainsaw couldn’t fix anyway,” comments Lee. Later plantings were more randomised.

It seems ironic, but those first plantings have grown so dense that the rangers are now cutting out groups of 10 to 12 trees to create light wells and open up the dark forest. No more planting is needed on Tiri; anyone who wants to plant trees nowadays must go to one of the other islands in the gulf modelled on Tiri’s success, of which there are now plenty.

Tiri’s exposed eastern coastline is considerably more rugged than the west, which looks back towards Auckland. A large pohutukawa cantilevers from the cliff face—its root system anchored deep in the rock allows the upper half of the tree to defy gravity and stabilises the escarpment at the same time.
Tiri’s exposed eastern coastline is considerably more rugged than the west, which looks back towards Auckland. A large pohutukawa cantilevers from the cliff face—its root system anchored deep in the rock allows the upper half of the tree to defy gravity and stabilises the escarpment at the same time.

As the Tiri project took root, Craig and Mitchell wrote similar propos­als for other islands in the Hauraki Gulf—Rangitoto, Motutapu, Motuihe and Motuora Islands —envisioning them as “relief valves” for Tiri, in the same way that Tiri had been created to take the pressure off Little Barrier Island. They imagined that as the birds prospered on pest-free islands they would migrate to other islands, even­tually turning up in the backyards of people on the mainland, which would spread the conservation message fur­ther. For over a decade little progress was made toward their vision, but now conservation in the wider Gulf has sprung into life and the speed with which some sanctuaries are developing is dizzying.

And the birds themselves are get­ting into the act: twelve kilometres south of Tiri, the residents of Rakino Island have been delighted by the ar­rival, under their own wing-power, of a handful of bellbirds. The odd kaka­riki (or red-crowned parakeet) has also been sighted there. Kakariki have also flown to the Whangaparaoa Penin­sula, where they are gradually making their way into suburbia.

The kakariki was the first species to be released on Tiritiri Matangi 34 years ago and since then ten more rare or endangered birds have been introduced. Without rats and other mammals to prey on them, the birds have bred eagerly, so much so that the island is running out of room and food for some species. Over their first year, there is a high mortality among the juveniles of many species.

The solution is to “farm” the island, capturing birds and transferring them to other sanctuaries. Saddlebacks were sent to Mokoia Island in Lake Rotorua as early as 1992, stitchbirds and saddlebacks have helped populate the Karori Sanctuary in Wellington, whiteheads and North Island robins went to the Tawharanui Peninsula in 2007, and stitchbirds and whiteheads are breeding in the Waitakere Ranges’ Ark In The Park project.

Certainly the birds regard the Gulf as a single entity: as well as the move­ments of seabirds, kaka fly from Lit­tle Barrier and Great Barrier to Tiri and are sometimes seen on the North Shore, and tomtits occasionally arrive on Tiri, presumably from Little Bar­rier Island.

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Tiri guide Barbara Hughes used a Royal Society Teaching Fellowship year to organise the transfer of tomtits to Tiri. For months beforehand she and a team of volunteers regularly visited the Hunua Ranges in South Auckland, feeding the tomtits meal-worms, and getting to know the birds within their territories. “They became my little mates,” she says. “And I felt bad about translocating them as I knew some birds wouldn’t make it.”

In April 2004, four teams of work­ers caught and banded 32 birds over two days, drove them in individual boxes through Auckland’s rush-hour traffic and then flew them to Tiri by helicopter. But after the first two weeks the released birds were observed infrequently. Barbara visited the Hunuas two months later. “There, in his old territory, was a banded male, Mr RG. I couldn’t believe it! He had flown over 56 kilometres back to his original territory. Taking the direct route would have required flying over 10 kilometres of open water which is one amazing feat for a non-migratory 10 gram bush bird.” Although tomtits are still occasionally seen on Tiri, this transfer is not yet considered a success.

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The supporters of Tiritiri Matangi Inc. (SOTM) was formed in 1988. Apart from two full-time DOC rangers, SOTM members do most of the physical work on the island; the tracks and boardwalks are built and maintained by volunteers, who also help with bird and reptile research and transfers, and act as volunteer guides. SOTM also raises most of the money, with half of its income coming from guiding and the shop. SOTM has funded many of the new buildings on Tiri including the Ray and Barbara Walter Visitor Centre opened in 2006.

Jennifer Haslam has served Tiri in two roles, first as a volunteer guide then, since 2005, as a DOC ranger. “Without the volunteers,” she says, “there’d just be nothing happening out here, so you wouldn’t have the momentum to get funding. More and more, the rangers are in a coordination role.”

This symbiotic relationship be­tween DOC and SOTM has become the standard model for restoration programmes throughout the country. Even the venerable Little Barrier Island sanctuary, established in 1895, has had its own Supporters’ Trust since 1997.

My own involvement with Tiri began when I joined a Forest and Bird working weekend on the island some 12 years ago. I was in the first guiding intake in 1998. On return­ing home after 20 years overseas, I had been freshly captivated by New Zealand’s beauty. It seemed like paradise, and I wanted to help keep it like that.

Greg, a particularly self-assured takahe, often mills around the wharf in the hope of supplementing his diet of shoots and insects with the more exotic stuff found in backpacks. Visitors are instructed not to feed or interact too much with these animals, but takahe, like keas, set their own social agendas, and have been known to steal that which is not given freely.
Greg, a particularly self-assured takahe, often mills around the wharf in the hope of supplementing his diet of shoots and insects with the more exotic stuff found in backpacks. Visitors are instructed not to feed or interact too much with these animals, but takahe, like keas, set their own social agendas, and have been known to steal that which is not given freely.

Having written a book about Tiri, I’m frequently invited to talk to community groups about the island. In every group, even as far afield as Rarotonga and Iceland, I meet peo­ple who are proud to have planted trees on the island. Tiritiri Matangi is famous worldwide in conserva­tion circles, both for the wonder of its burgeoning bird life, and for the remarkable volunteer contribution that continues today.

“For me, it’s fabulous that so many people appreciate Tiri,” says Craig. “In the 1980s we scientists were privi­leged to be able to go to places like Tiri. But now there’s a queue!”

Last year 13,000 visitors were guided on Tiri. According to DOC ranger David Jenkins, managing the numbers of people who want to come to Tiri is now the major challenge for the island. “DOC is already under pressure to allow more visitors. But more people would put increased pressure on the facilities and the en­vironment. And it would increase the ever-present threat of a biosecurity breach.”

Jenkins moved to Tiri last year af­ter several years working with the Mo­tuora Restoration Society. Heighten­ing his concerns about biosecurity was the news that a rat was loose on Mo­tuora Island, which is a kiwi crêche. The rat, which probably arrived by boat, was caught two weeks later. And a few months ago the crew of the Tiri­bound ferry found a hole chewed un­der the door and food packets strewn around the boat. Cancelling that day’s trip to the island, the crew laid traps, which caught a large rat. The conse­quences could have been devastating.

“But the threat comes not just from mice or rats,” says Jenkins. “A vi­rus or bacteria could be so much more devastating.” In fact, a rare strain of salmonella which arrived on Tiri in 2006 quickly wiped out one quarter of the precious hihi (stitchbird) popula­tion. The disease forced the postponement of a proposed transfer of hihi to the Waitakeres until the outbreak was deemed under control. Such occur­rences remind us how vulnerable these endangered species are, and emphasise the need to establish more populations of them.

One tenacious invader has been the Argentine ant. These aggressive intro­duced ants are spreading unchecked throughout mainland New Zealand, eating everything in their path. They are one of the world’s most invasive and problematic ant species. In 2000 DOC entomologist Chris Green spotted a line of them walking up a tree near Tiri’s wharf. Although he took immediate action, it has taken years to contain the invasion. It’s hoped that Tiri will be declared ant-free later this year. Green now finds himself regard­ed as something of an “Ant-Buster”, advising other countries on methods for eradicating ants.

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With the island’s suite of land-birds almost complete—only rifle­man are still on the wish list—the focus has switched to reptiles. In 2003 tua­tara were brought by helicopter from the Mercury Islands, in a release or­ganised and paid for by SOTM. Some of the sixty adult tuatara were carrying eggs at the time, and now babies are be­ing found. Shore skinks and Duvaucel’s geckos have also been introduced, with more lizard transfers planned.

The populations of lizards, as well as of birds, suffered during Tiri’s past history: When Maori arrived some 600 years ago they released the Poly­nesian rat, the kiore, as a food source. After the farming was stopped in the 1970s kiore numbers grew to plague proportions and the starving rats ate everything they could find, probably wiping out many lizard and insect populations in the process. The kiore were eradicated in 1993 by an aerial drop of poison baits.

It was thought that the only rep­tile species to survive this predation were moko skinks and copper skinks, but to everyone’s delight the com­mon gecko, a small, brown lizard, was recently discovered on the island. The first sign was a trail of little foot­prints left in a tracking tunnel: placed around the coast, tracking tunnels provide an early-warning system of an invasion of mammal predators. A few individual geckos had probably survived among the rocks on Tiri’s rugged eastern side where rats would not commonly venture.

Massey University Research Tech­nician Marleen Baling has been search­ing for the geckos. “We go out at night looking in cracks and crevices and on shrubs and trees.” She confirms that,15 years after kiore were eradicated, the geckos are quite numerous. “We’ve caught up to 17 individuals a night, across the whole population spectrum: juveniles, gravid females and aggressive males.”

“We’re also finding geckos on flowering pohutukawa trees, licking nectar from the flowers.” This phe­nomenon has almost entirely disap­peared from New Zealand’s ecology, but it’s thought that many indigenous plants with nectar-bearing flowers would originally have been pollinated by lizards.

Unfortunately Marleen has found no trace of the attractive green geckos which were reported by Tiri lighthouse keepers until the 1960s.

A group of students from the University of Auckland explores a portion of coast as part of their environmental studies course. They are guided by Professor Neil Mitchell, one of the two individuals who first conceived of Tiri as a revegetated and restocked open sanctuary. The island, which had been intensively farmed, was stripped of almost all its native bush. Historical aerial photographs show the degree to which tree planting has transformed the island (bottom).
A group of students from the University of Auckland explores a portion of coast as part of their environmental studies course. They are guided by Professor Neil Mitchell, one of the two individuals who first conceived of Tiri as a revegetated and restocked open sanctuary. The island, which had been intensively farmed, was stripped of almost all its native bush. Historical aerial photographs show the degree to which tree planting has transformed the island (bottom).

Large native insects and flax snails are also on the island’s wish list. “People tend to think that Tiri is finished,” comments Mitchell. “Yet in many respects it should still be con­sidered as work in progress. We have shown what can be done in island restoration, and inspired many sub­sequent, successful emulations. How­ever, John [Craig] and I would be the first to admit that there are several key aspects we didn’t adequately ad­dress, such as the lack of any adequate sea-land linkage.”

According to Mitchell, Tiri would have been a sea bird island with its forest floor a maze of seabird bur­rows. In many respects the sea birds would have provided the foundation of the island’s ecosystem, transport­ing the ocean’s fertility to the land via their droppings (guano) and in the food brought on land for their off­spring. It is this remarkable fertility, embedded in the land from thousands of years of nesting sea birds, that probably helped the trees that volun­teers planted on Tiri grow so quickly. But nowadays only small numbers of grey-faced petrels and diving petrels nest on the island.

“Along with the sea birds there would have been tuatara, other rep­tiles and invertebrates,” Mitchell explains. “It is not too late, but there needs to be a programme to reintro­duce additional sea birds as has been done on Mana Island.”

This open sanctuary, just north of Wellington, has pioneered a technique in which sea bird chicks are brought to the island, placed in artificial burrows and hand-fed (on tinned sardines) until they fledge and fly away. Sea birds normally return to the place where they hatched, and after a few years at sea some of the Mana birds have returned to breed on their adopted island.

“If Tiri is to support the diversity of ground reptiles and invertebrates it once did,” warns Mitchell, “Sea birds are essential. Until then it will remain an incomplete system.”

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Tiritiri matangi has created an environment in which our native species can flour­ish, provided a showcase for our native birds and shown what can be achieved with conserva­tion. The island’s future looks rosy, although climate change is likely to affect small, dry and exposed islands like Tiri more than mainland sanctu­aries. An increase in extreme weath­er—higher winds, more storms, more drought and extremes of temperature puts pressure on enclosed ecosystems. In the past two summers of little rainfall, trees have wilted, berries shrivelled in the heat, and the ground baked hard, leaving robins unable to find worms or insects. Any source of water was mobbed by thirsty birds. Dams almost dried up, leaving the brown teal homeless and resulting in the death of a spotless crake which got stuck in the mud. Yet paradoxi­cally, the long spell of settled weather resulted in a spectacular flowering season this summer, and there were more insects than usual.

Equally, severe storms can do great damage. Tiritiri Matangi is well-known for having some of the strong­est winds in the Hauraki Gulf, (its name means “buffeted by the wind”), but in July 2007 a gust of 180 km/h (97 knots) broke every record. The storm killed a metre or so of the tree­tops in Wattle Valley, and the salt-laden winds destroyed many leaves. For months afterwards skeleton leaves carpeted the ground, and the bush appeared uncannily transparent—one could see much further into the for­est than previously. The resulting increased light to the forest floor has actually encouraged a rash of young seedlings, although their growth can’t compensate for the loss of so much foliage from the canopy.

Those people who care for the island feel responsible for it and its precious inhabitants; but as Ray Wal­ter—the former live-in manager of the island—said, “If we all walked away tomorrow, the island would just carry on.” Meanwhile, the bellbirds, which have migrated from Little Barrier to Tawharanui, and from Tiritiri Ma­tangi to Rakino, are the vanguards of future bird migrations. And as Tiri’s bird populations increase and other sanctuaries flourish, it is likely the Hauraki Gulf will resound again with “melodious wild musick”.

Looking north from a northern bay, Kawau Island shimmers on the horizon. In the region of The Arches, ragged cliffs eroded by sea and buffeted by high winds make access to Tiri’s east coast difficult.
Looking north from a northern bay, Kawau Island shimmers on the horizon. In the region of The Arches, ragged cliffs eroded by sea and buffeted by high winds make access to Tiri’s east coast difficult.

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