Frank Greenall: Extinction is forever

Big Bird: Whanganui Regional Museum's Mike Dickison with the mortal remains of an extinct moa

A place I was visiting recently was graced by a few pohutukawa trees. True to its billing as the New Zealand's Christmas tree, the first flower popped its crimson stamens out last week, soon joined by a bevy of others.

Equally true to form, the local tuis swooped within an hour or two, sticky-beaking their way around the display for some nectar treats.

Luckily, no sign of myrtle rust … yet. It's sobering to think a fungal diseasehas the power to take out not only pohutukawas, but a whole raft of species, much as the Martian invaders in H G Wells' War of the Worlds were felled by the common cold.

A recent revisiting of a collection of recordings of the calls of now extinct birds housed in an American archive unexpectedly unearthed a recording of both male and female huia calls. Not the real thing – the last reported sighting of a huia was in 1907, when field recording was a rarity.

This was a recording made in the 1940s of Henare Hamana whistling the huia calls he had been taught as a boy.

The young Henare had been on several unsuccessful expeditions hoping to find remnant pockets of the elusive bird — prized for their tapu feathers — in the Ruahine ranges, but at least he was able to leave a facsimile of their distinctive calls.

Hearing the calls (available via Google) is an eerie echo of the phantom bird, and a poignant reminder of the ease with which a species can slip into oblivion.

Luckily, the brief-flowering pohutukawa is necessarily not the tui's only source of nourishment, and should it get rusted out, wouldn't take the tui with it.

I have lived in a place where, one year, rewarewa, flax and kowhai simultaneously flowered — all favourite tui treats — but the tui's first and most favoured port of call was a grevillea. If you want to attract tui, plant a grevillea as well as natives: they also have the advantage of flowering for many months longer).

But perhaps the wonder is that more species don't succumb to the omnipresent array of microbes, including ourselves. There are 500 species of bacteria in the human mouth and throat alone, and about 400 trillion bacteria in a human body. That's a lot of bacteria to keep in the good books with.

Frank Greenall

The world of science now says that we're currently in what's been labelled the Sixth Age of Extinction, relatively brief periods in which multiple species are wiped out. The previous five ages were all caused by natural catastrophes – meteor impact and such like — but the difference with the latest one is that humankind itself is the bogeyman terminator.

The current rate of species extinction is running at approximately 100 times greater than in pre-human times, and most of it revolves around loss of habitat caused by a whole hatful of human-related reasons.

Unfortunately, New Zealand's right up there in the extinction stakes. We lost major species like the moa and Haast's eagle even in pre-European times. And presently, between the maui and Hector's dolphins, the hoiho and New Zealand sea lion, and a whole gamut of both land and sea birds and native fish, we have a rapidly lengthening endangered list.

Some say, "So what?'. Species have always come and gone, including humans, as with the Neanderthals. But as some wag proffered: "Google, Microsoft, Toyota and General Electric have all crunched the numbers and come to the conclusion that planet collapse would be bad for business."

Each species is a specialised trestle that helps support an infinitely complex web of interlinked ecology. Kicking the odd trestle out isn't going to collapse the whole chain, but kick out enough and it will. Right now, we're trashing an awful lot of trestles.
Extinction is a long time. When it's man-made, it means having to say you're sorry forever.