Why do we need to be Predator Free? – Brent Beaven PF2050

The goal is to eradicate rats, possums and stoats from Aotearoa by 2050. It will take a lot of hard work, money, research, collaboration and commitment across generations of Kiwis. So why is it necessary? This is the second blog in this PF2050 series.

By Brent Beaven, Programme Manager Predator Free 2050

Aotearoa has some of the most ancient and unique wildlife on Earth. Pulitzer Prize-winning American author Jared Diamond once wrote that our biota was “as close as we will get to the opportunity to study life on another planet.”

Eighty-five million years ago, mammals hadn’t yet spread to the southern reaches of Gondwana, so that when Zealandia split from the ancient supercontinent, they missed the boat.

The passengers were instead birds, plants, insects and reptiles. That’s why our only native mammals are those that could either fly here (bats) or swim here (seals).

With four-legged mammals missing, birds evolved to fill the vacuum. Kōkako climbed like squirrels, while kiwi hunted invertebrates in the leaf litter by smell, much as a hedgehog might. The only predators were other birds: the huge pouākai (Haast’s eagle) which was a moa-killer, Eyles’ harrier, and the whēkau (laughing owl). These raptors hunted by keen eyesight, so their prey evolved cryptic camouflage — the mossy green mosaic of the kākāpō, the blue-grey “wet rock” look of the whio — and they learned to keep perfectly still when predators were about.

Evolution is driven by danger or need, and without much of either, Zealandia’s creatures were loath to change. That’s why our fauna is famous for its ‘ancient’ species: the tuatara, a relic from 200 million years ago; our native frogs, all but unaltered in 70 million years. Noted Australian palaeontologist, Tim Flannery, called it “a completely different experiment in evolution to the rest of the world.”

Crucially, catastrophically, it’s also well-known for being rather smelly.

Unlike their counterparts overseas, many of our birds, our snails, our lizards — even our wētā — give off a perfume so strong and distinctive that sniffer dogs can be trained to specialise in tracking these various creatures.

Eight hundred years ago, Zealandia became Aotearoa when the great waka arrived. Aboard, there were kurī (dogs) and kiore (rats), and their sharp sense of smell led them straight to native wildlife, which obligingly stayed rooted to the spot.

Four hundred years later, the Europeans brought a whole other bestiary of keen-nosed predators — more rats (most disastrously, the ship rat, an agile tree climber), mice, possums, stoats, ferrets, weasels, hedgehogs, cats and pigs.

Meanwhile, the forests and wetlands continued to vanish before the flint and the axe, so that within 750 years of human arrival, half of New Zealand’s vertebrate fauna had disappeared.

At least 45 bird species went extinct.

Plus three frogs, three lizards, a bat, a freshwater fish and as many as nine plant species are gone forever. We will never know how many invertebrates we’ve lost. Aotearoa was ground zero for one of the worst extinction episodes in modern history. Haast’s magnificent eagle, Eyles’ harrier, and the laughing owl are all gone, along with many of the creatures they called food.

Sadly, that’s not just natural history. Today, some 4000 native species are still at some kind of risk – one of the highest proportions in the world. Around a quarter of them are in real danger of extinction. Almost 160 are getting management at only one site, which means those populations could be lost to a single disaster. There are many causes: loss of habitat or preferred food; competition from exotic species; pollution; even climate change, but overwhelmingly the problem continues to be those sharp-nosed introduced predators.

Without pest control, 95 per cent of young kiwi don’t make it to their first birthday.

If we were to let them, introduced predators — mainly stoats — would carve 2.5 per cent off Northland kiwi populations every single year. To extrapolate that rate of loss across all kiwi species around the country is to conclude that, without our help, they could be extinct in the mainland wild within two human generations.

Every night, dozens of other native species are plundered. In 2009, Landcare Research ecologist John Innes calculated that possums, stoats, ferrets, weasels, rats, mice, hedgehogs, cats and pigs kill more than 25 million native birds each year.

The wonder of those numbers is that our native species have even hung on this long, and that’s in part thanks to many decades of effort by conservation and pest control workers and volunteers.

Historically, the battle against predators has tried to defend a line, using traps, bait stations and aerial poisoning to blunt the worst of their destruction. It has always been about buying our wildlife a bit of breathing space to recover their numbers.

The Predator Free proposition is a step change from piecemeal control, to coordinated, progressive nationwide eradication. At present, we spend tens of millions of dollars every year on the treadmill of temporary control — a gambit with no end.

The Predator Free 2050 strategy is about funding innovation, testing and implementation to put an end to the ravages of rats, stoats and possums once and for all. Rather than endlessly meeting maintenance costs, PF2050 is about up-front investment in an enduring solution, leaving much lower “tail costs”.

Importantly, it literally pushes out the boundaries of predator control, swapping intermittent, localised operations for a sustained push towards eradication across entire landscapes, both forests and farmland, and in our cities.

Best of all, our biodiversity can thrive again, free from the depredations of the three most destructive pests to have reached our shores. Aotearoa holds one of the most unenvied extinction records of any nation and PF2050 offers us the chance of a new reputation, as the first in the world to take a stand for our taonga.

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Find out more about our work controlling predators, plus a practical guide to trapping and information about the latest predator control innovation, head to our website: https://www.doc.govt.nz/nature/pests-and-threats/predator-free-2050/

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