New Zealand has decided to do something almost no other country has tried at a national scale. By 2050, the government wants the entire archipelago to be free of invasive mammalian predators such as rats, possums, mustelids and now feral cats so that native wildlife has a real chance to recover.
Official documents describe a country with one of the highest proportions of threatened species on Earth, where introduced predators kill an estimated 25 million native birds every year.
In simple terms, Predator Free 2050 is an attempt to stop that quiet collapse. Over the last thousand years, roughly 40 to 50 percent of New Zealand’s bird species have disappeared, and more than half of those extinctions are linked to predation by mammals that never existed there before humans arrived. For people waking up to a thin dawn chorus outside the bedroom window instead of the wall of sound early settlers described, that loss is no longer abstract.
To understand why the numbers look so grim, you have to rewind deep into geological time. New Zealand drifted away from the supercontinent Gondwana more than 80 million years ago and evolved without land based mammal predators. Apart from a few small bats, there were no native mammals at all.
Birds took over roles that mammals fill elsewhere, so many became flightless, nested on the ground or evolved slow, trusting behavior. Tuatara and giant insects such as wētā shared the forest floor with them, creating an ecosystem that looked almost prehistoric. For predators that arrived later, it was an open buffet.
Human settlement set that cascade in motion. Polynesian voyagers brought the Pacific rat centuries ago, and European colonists later added ship rats, stoats, weasels, ferrets, possums and cats for fur, farming and crude pest control. These species found prey with no fear of mammals, little competition and plenty of food, so their populations exploded while native birds, bats and reptiles shrank.
Rats, possums and mustelids on the front line
Conservation staff often single out rats as public enemy number one. Three rat species now occupy forests, farms and cities, eating eggs, chicks, insects and seeds. Long-term monitoring shows that many forest bird populations crash once ship rats and stoats establish themselves, and that they recover only where predator numbers are held very low over large areas.
Possums are the other heavyweight. Brushtail possums, introduced from Australia for the fur trade, are now estimated at around 30 million animals after decades of control, with earlier estimates closer to 70 million.
They strip leaves, flowers and buds from native trees, raid nests and spread bovine tuberculosis in cattle. Vegetation surveys and disease studies link them to canopy dieback, erosion and expensive livestock management, costs that eventually show up in farmers’ budgets and even in the price of milk at the supermarket.
Mustelids, particularly stoats, are precision hunters. Brought in to control rabbits, they turned instead to native birds and bats. Research on the endemic kaka parrot illustrates the stakes. In one Department of Conservation project, kaka nesting success rose from virtually zero to 57 percent of nests fledging chicks at sites with intensive stoat and possum control, while survival of nesting females increased from 16 percent to 79 percent.
Without that kind of intervention, predators remove breeding females and whole populations can slide toward extinction even when the forest still looks green and healthy.
Feral cats step into the spotlight
For many New Zealanders, the most emotionally charged part of the plan involves cats. Feral cats, which live and breed without human care, now roam bush and farmland in numbers estimated at more than 2.5 million. In late 2025 the government formally added feral cats to the Predator Free 2050 target list after years of debate in a very cat-loving nation.
Conservation Minister Tama Potaka has called them “stone-cold killers” that drive shorebirds such as the southern dotterel, native bats and small reptiles toward extinction.
Pet cats are not included in eradication targets, but the line between a roaming pet and a feral hunter can blur. That is why animal welfare groups and ecologists are pushing for measures like compulsory microchipping and desexing so people who care about their cats can also help protect the wildlife outside their back door.
A national moonshot with local footprints
In the scientific literature, Predator Free 2050 is often described as a national “moonshot” for biodiversity, ambitious and risky yet potentially transformative. A strategy review released in 2025 reaffirmed the core goal of eradicating rats, mustelids and possums nationwide by mid century, with feral cats now added to the list of priority predators.
Delivering on that vision will take serious money and a lot of everyday effort. A recent brochure from the Department of Conservation notes that the program has invested about 43 million dollars in new tools, research and software during its first five years.
At the same time, more than 5,000 local groups and iwi-led partnerships are already part of the Predator Free movement, turning backyards, school grounds and city parks into pieces of a national restoration puzzle. For many households, checking a trap on a weekend walk is becoming as routine as taking out the recycling.
The trouble is that the clock is moving faster than politics and technology. Reviews of predator control projects warn that robust, long-term monitoring is still rare, and that some operations deliver less biodiversity gain than hoped, especially where habitat loss and climate change are not addressed alongside predator removal.
At the same time, economic analyses suggest that a coordinated push toward a predator-free New Zealand can be ecologically achievable and economically defensible over several decades, compared with the growing cost of inaction.
In practical terms, New Zealand is weighing the lives of individual invasive mammals against the survival of entire species that exist nowhere else. Can killing millions of animals really be called conservation? For many ecologists and community leaders, the uncomfortable answer is that in a landscape reshaped by people, choosing not to act is also a choice that carries moral and ecological consequences.
Other island regions such as Hawaii and the Galápagos are watching closely, since what works in Aotearoa could become a template for repairing fragile ecosystems around the world.
The official visitor brochure on Predator Free 2050 was published on the Department of Conservation site.
