The story of the bird on our $100 note.

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Reserve Bank of New Zealand

Banknotes are sometimes thought of as a nation’s business cards, and the images upon them reflect what is unique about a country. The endemic birds and plants that adorn our new notes (released over the past year) remain the same as on the last series, though the images have been updated.

Mōhua, the sparrow-sized songsters with bright yellow heads and breasts on the $100 bank note were once one of the South Island’s most common bush birds, from the coast to the treeline.

“I feel like I’m visiting the past when I see them,” says Graeme Elliott, a scientist with the Department of Conservation. “Plus they’re cute as hell.”

Elliott took the picture of the Eglinton Valley scene reproduced on our previous $100 note. The bird on the new note was photographed by Rod Morris, and background images captured by Wellington photographer Rob Suisted, both of whom contribute to this magazine.

Like the other banknote birds, mōhua (also known as yellowhead) have been visiting our purses since they appeared on our money in 1991. There were tens of thousands of them then, and millions in the previous century. Today they are estimated to number less than 5000, in isolated populations occupying less than five per cent of their original range.

Their magnificent throaty trill (they were once known as bush canaries) has disappeared entirely from Stewart Island and the northern South Island.

Mōhua hunt insects, flicking leaf litter away from tree crevices, or snatching invertebrates from foliage, and from under bark and moss. They sing musically as they move through the treetops, foraging in pairs, family groups or flocks, depending on the time of year.

They nest and roost in holes in trees, but when penetrated by rats or stoats, those hiding places become traps. Not only are eggs and chicks eaten, but also the adults, and with them dies hope of future breeding seasons too.

However, predators are far less common at high altitude in South Island beech forests, except during ‘mast’ years when the trees seed. In between these masts, the population of mōhua tends to “bounce back a bit”, according to Elliott. “That’s why they survive in beech forests,” he says. “They’ve simply been eaten out of other remaining bush.”

The mōhua rescue strategy is similar to that employed for many of our threatened species—move some to predator-free islands, and pepper mainland forests with 1080 poison, and often stoat traps, soon after beech seeds fall. Poisoning and trapping works: twice as many mōhua survive in treated areas. But eventually another mast year occurs, predators reinvade, and the costly cycle begins again.

Like last year, 2016 is a heavy mast year for beech. In response, DOC will carry out a $20.7-million predator control programme code-named Battle for our Birds. The main mōhua populations will be targeted because of the adults’ vulnerability to predators.

Little public money is spent exclusively on mōhua, because their main requirement is pest control, which protects all the native flora and fauna in their ecosystem. DOC runs a mōhua recovery group, monitors key populations and works with private sponsors to co-ordinate bird translocations to and from predator-free islands.

In the South Island Ngāi Tahu consider mōhua to be a taonga, a treasure worth more than money. The presence of the bird on our highest denomination seems to echo that sentiment.

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