No More Pests

February 24, 2017
Heather Price-Wright
New Zealand has an ambitious plan to get rid of rats and other invasive mammals.

New Zealand plans to get rid of rats, possums, and other invasive mammals. The country hopes to save native birds.

Rats are not many people’s favorite animal. But most people have to learn to live with them. Not in New Zealand. Last July, New Zealand’s then–prime minister, John Key, announced a plan to rid the archipelago of rats and other mammals by 2050.

In New Zealand, rats are an invasive species. They arrived on boats, along with human settlers, in the 1200s. When they were introduced to the area, the rats ate the native birds.

Humans also brought other mammals, like stoats and possums. Stoats are similar to weasels. The mammals were brought in to eat another invasive species: rabbits. Instead, the stoats fed on native creatures.

Kiwis are flightless. There are about 68,000 of the birds left in New Zealand. Stoats are their biggest predator.


Possums were introduced for their fur. But their population grew quickly out of control. Possums feed on the eggs and young of native birds.

One of the reasons invasive mammal populations grew so quickly is that New Zealand is home to almost no native mammals. Most of its native species are birds. Many, like the kiwi, which is the national bird, are flightless. When mammals arrived, flightlessness became a big problem for the birds. Now mammals kill about 25 million native birds every year. Several species are on the brink of extinction.

A Big Goal

Eliminating predatory mammals is not new for New Zealand. The country has gotten rid of rats on some of its smaller islands. In those places, bird species that were almost wiped out have begun to flourish.

New Zealand now hopes to study and improve upon the methods used in those areas. The government has pledged about $20 million to the project. Other money will come from local governments and private businesses.

The government of New Zealand recommends several ways to get rid of pests. Traps and bait stations are the main types.


The plan is “the most ambitious conservation project attempted anywhere in the world,” Key wrote in a statement. “But we believe if we all work together as a country, we can achieve it.”

It is a big goal. But scientists say it could happen. “I really do think it’s possible,” James Russell, a scientist in New Zealand, told the AP. “It will require people working in every nook and corner of the country.”