The story of the bird on our $50 note.

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Reserve Bank of New Zealand

The huia is extinct, the saddleback survives only in predator-free sanctuaries, and the South Island kōkako hasn’t been seen in decades. Yet their wattlebird cousin, the North Island kōkako, is alive and well as a result of aggressive conservation efforts.

In 1978, the bird on the back of our $50 note was critically endangered, but lingered in a shrinking patch of virgin forest in Pureora Forest Park in the middle of the North Island. Large tracts had been clear-felled and burnt, and a block of prime kōkako habitat containing ancient tōtara was next in line.

The Minister of Forests insisted the logging go ahead to fulfil high-value contracts with local sawmills.

A group of activists, led by long-haired, barefoot Stephen King, refused to allow continued logging. After negotiations failed, the protesters stationed themselves high in the tōtara before the loggers approached.

The trees were spared. Enormous public support for the cause resulted in a moratorium on the logging of native trees in Pureora, allowing time to assess whether selective logging (which targets just the largest, oldest trees) also disadvantaged kōkako.

During the moratorium, scientist Rod Hay collected research on kōkako biology. (Hay also captured the background image of Pureora Forest on the old $50 note. Geoff Moon photographed the bird; the kōkako on the new banknote, released last year, was captured by Rod Morris, and the forest scene by Rob Suisted.) He discovered that kōkako defend territories, and must find sufficient food within them. The perching plants and vines borne by the forest’s oldest trees, he discovered, offered a more important food source than younger trees. The untouched, primary forests were home to the most birds, while selectively logged tracts hosted fewer.

The moratorium became permanent, which was a major step towards the end of native forest logging on public land.

“Kōkako became a political agent,” explains ecologist John Innes, a long-time member of the Department of Conservation’s kōkako recovery group. The birds’ famous song, often sung as a duet, assisted their popularity; Innes wrote in the recovery plan that it “is flung… from the tops of emergent trees at dawn; it fills the sky, and then settles like a huge blanket down through their forest territories”.

But the population of organ-birds, as kōkako were once known, was still decreasing in the 1980s, even with remaining forests secure. “We were going to kiss them goodbye on their way out,” Innes told me. With colleagues, he established that rats and possums were attacking eggs, chicks and incubating females. The resulting shortage of females had led to male-male unions, which couldn’t contribute to population growth.

Today, strident predator control by DOC and many volunteers has resulted in kōkako becoming one of the few threatened species that are actually recovering. In the 1990s, there were just 330 male-female pairs; today, there are almost five times that many. And their range is expanding, the result of nine successful translocations to predator-controlled areas.

The former logging region of Pureora has also been transformed, into a hub for mountain biking, tramping and hunting. The haunting song of 430 kōkako pairs rings through its forests.

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