Birds like the iconic New Zealand kiwi had no predators before the introduction of rats to the archipelago. They are decimated by these rodents, which threaten biodiversity.
New Zealand is hunting rats, with one goal: to eradicate them completely by 2050. And the first results, on a local scale, are rather encouraging. This very ambitious plan, “Predator Free New Zealand”, was launched in 2016 via a joint venture in which the government invested 28 million New Zealand dollars (17 million euros). Three varieties of rats were then officially classified as invasive species and a threat to biodiversity.
It’s not that rats are more numerous than elsewhere, it’s just that in New Zealand, before their introduction in the 13th century by the Polynesians and then 600 years later by European settlers, their prey had no never had any predators. On the archipelago, birds make their nests at ground level, some species can barely fly. The rats, eating their eggs, competing with them for food, wreaked havoc. Along with their ferret and opossum pals, they have managed to munch 25 million birds every year. The kiwi, for example, may be the national emblem, but most New Zealanders have never seen a single one in the wild. There remain on the island less than 70,000 individuals.
Wellington’s example
Making the rats disappear will make the birds come back. A first assessment has just been made in the capital, Wellington. It is rather conclusive. A BBC journalist went to see on the spot. The project, financed by public and private funds, employs 36 people, but it relies above all on hundreds of volunteer hunters transformed into real exterminators, equipped with traps, peanut butter, anticoagulant poison and a GPS application. . Cameras have been installed in strategic places; each rat found dead is reported and sent to the laboratory for autopsy. Rats are now fewer, native birds have made a comeback. To the west of the city an eco-sanctuary has been protected by a huge fence of more than eight kilometers, the rats no longer put their paws there.
Can the method used in Wellington work across an entire country? That’s the whole point. To date, only one territory in the world can claim to have eliminated all rats is an island in the South Atlantic called South Georgia, which is about 70 times smaller than the New Zealand. It’s not win.
The government wants to go there in stages, it is already aiming for one million hectares free of rats by 2025. But environmentalists are skeptical. They believe that the rat hunt mobilizes too many means and that it costs too much. The only solution would be to turn each inhabitant into a rat hunter. A school on a very small island in the far south of the archipelago, Stewart Island, took the test last November, with rewards at stake. It worked very well: in 100 days, the students killed (with pride) more than 600 rats.