Alexander Turnbull Library


Fifty years ago, the government was burning swathes of native forest, using napalm as an accelerant. But under one particular forest was a hill, and under that hill was a system of caves filled with the bones of the dead: moa, giant eagles, tiny songbirds. If the forest went, the fossils would go, too.

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In 1980, Richard Dell had recently retired as director of the National Museum in Wellington. His idea of retirement was to drive around the country looking for things to save. He arrived on the West Coast and happened to meet menswear-seller and fossil hunter Phil Wood, who told him: “I’ve got a cave full of bones no one’s interested in.”

Dell was a born conservationist. “Put that boulder back” was a family motto. At the age of 10, he had opened his first museum (molluscs) in the henhouse in a backyard in Auckland. He listened carefully to Wood’s account of Honeycomb Hill, the caves he had found and that no one cared about.

Meanwhile, a problem was emerging, in the form of an official known as the assistant conservator of forests. Honeycomb Hill stands in the middle of a valley named the Ōpārara Basin. The land belongs to the state, and was then under the control of the Forest Service. The primary duty of the assistant conservator at that time was not, in fact, to conserve forests but to ensure the supply of timber for the nation’s needs, and if not that, to make money from them in some way or other. The rainforest of the Ōpārara Basin had never produced a penny. Very well! Now it must pay its way.

It is hard to believe today some of the plans hatched by the Forest Service in the 1970s for the untouched bush on the West Coast of the South Island. First, the most valuable trees would be cut down and winched out for sale. Then exciting new technologies could be brought to bear. All the trees left standing would be bombed from the air with herbicides, with Agent Orange, for instance, contaminated with dioxin, as used by the US Air Force to strip the communist-concealing jungles of Cambodia and Vietnam. The dying trees could be left to dry for about five years and then bombed again with an incendiary such as napalm, also used in Vietnam.

Poisoned, blackened and burned, the land would then be ready for a cash crop. In this case, pine trees.

It was the philosopher Thomas Hobbes who first advised humankind to “make war on nature”, our situation in the universe being so horrible, the argument ran, we might as well make ourselves comfortable. But not even gloomy-minded Hobbes could have imagined these weapons of war turned on a primeval forest. After 40 years—in about 2020— a local paper mill could be built and the pines of the West Coast turned into wood pulp.

What’s the most efficient way to clear a native forest? Log the biggest trees, then use napalm to burn the rest. The photographs were entered in a 1983 competition set up by the Buller Conservation Group, specifically to generate photos of such burnoffs taking place in the Buller area.

The effect of deforestation on the caverns would be rapid and irreversible. Rainfall is high in the area. Heavy rain falling on bare hills would flood the labyrinth and debris would block the exits. All the strange and wonderful forms which rise from the floor and descend from the ceiling of limestone caves—stalactites, stalagmites, chandeliers, drapery and straws, fluted columns, frostwork and moonmilk crystals, rimstone pools, “paddy fields” and “mushrooms” of microcrystalline calcite—would be soon drowned and then dissolved by the acidity of the water.

Fossils which had lain there for thousands of years would be washed away and lost forever.

The sound of chainsaws could already be heard approaching Honeycomb Hill.

Here now was a battle worthy of Dick Dell. This was something worth saving! Again, names seem to rise from the heart of the matter. Dell and Wood vs Agent Orange and napalm. But how would the battle be joined? Back in Wellington, Dell alerted museum staff to the existence of the caves, and Wood contacted them separately from Westport. Within a few weeks a team of museum experts, from Wellington, arrived at Honeycomb Hill and Wood led them down into the dark.

What they saw amazed them Everywhere they turned their torches, it seemed, treasures lay half buried in fine red loam or grey fluvial silt. Taphonomy is the name given to the deposition of fossils. It has a soft footfall, this word, coined in Russia in the 1940s from taphos, the Greek for tomb or cave,  which suits the processes of fossil formation that take place unseen in silence and in darkness over many centuries.

This Haast’s eagle skull was collected from a cave called Eagle’s Roost in 1983, around the time the caves and their precious, long-dead inhabitants were under threat.

Here, for instance, is paleozoologist Trevor Worthy’s description of how Harpagornis or Haast’s eagle fragments were preserved in one cave at Honeycomb Hill named Eagle’s Roost: “Throughout most of the time that these were accumulating [on the cave floor], powdery microcrystalline calcite speleothems grew on the surfaces of overhead roof and walls, and weathering resulted in a fine rain of red-brown loam derived from the impurities of the limestone . . . During heavy rain, percolation waters periodically flowed over the cave floor . . . so that fossils were gently worked into the matrix of loam and fine calcite . . .

“At Eagle’s Roost, many bones of two different eagles were deposited on a central debris-cone which subsequently was eroded or dissolved away . . . The bones worked their way downward and laterally, so that the bones of the same bird ended up at least five metres apart, and one of these birds was only 16,000 years old.”

Fossils are fragile. Leg bones of moa—sturdy, sizable—often endure the longest. But even hefty fossils like these would not have survived the removal of the forest above. Unprotected, the cave would flood and the fossils go the way of the rest of the ancient skeletons.

Only 16,000 years old—that lovely “only” sums up the vast periods that Time sets aside to make a fossil.

Other natural features made Honeycomb Hill an unusually rich site, taphonomically speaking. The caves have about 70 entrances: several are sinkholes which are just wide enough for a bird to fly into but not out of again (few species can fly vertically upwards) and which are also filled with sunlight at some point of the day. The waterflow is persistent but the stream which had carved out the upper chambers has long since abandoned them for the deeper galleries. The only result of later floods in the upper caves is to cover fossils gently with more silt. And there was no sign, in 1980, of intrusion by mammals—by rodents, for instance, which gnaw bones and scatter them, or human beings who pick things up and carry them away.

For more than a century it was thought that Haast’s eagle could not fly and was, as Peter Walker writes, an “unlovely creature, which had gone rustling from corpse to corpse for its next meal.” But by 2008 it was clear: it certainly could fly, and it was “the apex predator … a kind of winged lion”.

Honeycomb Hill, its dark halls and galleries stretching in all directions, was a kind of Grand Palace of taphonomy. A preliminary report was made for the National Museum in which the writer could hardly contain himself. Even this little mark— ! —rarely sighted in scientific documents makes an appearance. “Honeycomb Hill is a tremendously exciting site . . . quite clearly of national, if not international importance . . . The state of preservation is quite outstanding . . . The bones of even very small birds have been preserved . . .  32 species of bird were recorded in this brief visit!”

The visitors stayed at Honeycomb Hill for two days. Since time was short, Wood took them only to places in the system where he had seen fossil deposits.

On the second day, he led them to the cave where he had found the wing bone of a Haast’s eagle in 1980. There, almost immediately, casually as it were, they found another.

The visitors were impressed, for eagle fossils were extremely rare. But then something even more impressive took place. They noticed a high shelf covered by an overhang of rock. One of them climbed and found the shelf covered with the bones of tiny songbirds—“thousands of them!” he wrote to me years later—“much smaller than matchsticks”.

One of the visitors was the museum’s curator of birds, Sandy Bartle, who had a special interest in the Acanthisittidae, a family of small wrens, drab in colour, quite insignificant in appearance, but of the most illustrious lineage.

The Acanthisittidae belong to the ancient guild of songbirds. Singing is not a universal characteristic of birds and it was probably “only” 70 million years ago (birds are thought to have evolved more than 100 million years ago) that an isolated group developed the polytonal syrinx, a voice-box with several muscles, allowing them to call in complex patterns.

For the first time in history, birds began to sing.

This little group evolved in a part of Gondwanaland which later became the south-west Pacific but, equipped with song, they then spread out around the world, mastering almost all environments and taking innumerable new forms.

As soon as Bartle found the shelf covered with tiny bones he began work, delicately excavating fossil remains which in any other cave would have been swept away or degraded thousands of years earlier. Working with him was an avian osteologist named Phil Millener. Within a few hours they had found remains of four of the five known species of Acanthisittidae —the rock wren, the bush wren, the rifleman and the stout-legged wren. Then Bartle came across a little skull which did not belong to any of them, and Millener realised it belonged to an unknown species.

Bones of the long-billed wren, removed from the cave system in April 1983, are now part of the collec-tion at Te Papa.

Further fragments were found, a picture built up and later a name was given. Dendroscansor decurvirostris was a little larger than the other wrens, had a longer bill and, to judge from the diminished keel of the breastbone, was flightless and ran fast like a mouse across scrubland rocks and forest floor. Here was a completely new member of the family of the Acanthisittidae, which had stayed home for 80 million years and hardly changed their appearance but were, in a way, the living ancestors of all the songbirds in the world.

This ended the threat to Honeycomb Hill. New Zealand is a young country and still turns to the natural environment—forest ferns and stars overhead—for its ID, so to speak, and proof of address. A new bird species, even one extinct for centuries and possibly never seen by a human eye, is a kind of national treasure.

The assistant conservator knew he was beaten, or perhaps he had a change of heart. He had come on the trip to Honeycomb Hill out of curiosity, and to keep an eye on the enemy. He and Bartle had crossed swords previously over conservation of forest habitat. Seeing the importance given to the tiny songbirds, and especially to the unknown new specimen, he retired from the field, and the sound of chainsaws and the march of pine seedlings abruptly ceased in Ōpārara.

The forest that protected these fossils—and was in turn saved by them—is now part of Kahurangi National Park and billed by DOC as “a true lost world experience”.

One day, in other words, a little wren fluttered down a sinkhole and couldn’t get out again. That event, instantly forgotten in the song-filled forest above, 12,000 years later saved the caves of Honeycomb Hill, and the same song-filled forest, from destruction.

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