North Island brown kiwi ‘no longer threatened’ as population swells to 20,000

“There’s still a huge battle to be fought, but this is hugely encouraging.”

Robertson has been working with kiwi for more than 30 years, and said a lot of work had gone into bringing the national bird back from the brink.

Before conservation efforts began, kiwi were in steady decline, and not much was known about what was causing the drop in numbers.

Being flightless ground-dwelling birds had not helped kiwi survive, especially with the introduction of predators such as stoats, rats and ferrets preying on nests and young hatchlings.

Kiwi also provide an easy target for dogs. In one incident, during the mid-1980s, a single pig dog was believed to have killed about 500 kiwi in Northland’s Waitangi Forest over two months.

If left to their own devices, kiwi chicks only have a five per cent chance of surviving to adulthood in the wild.

But with interventions such as Operation Nest Egg – where eggs were taken from wild nests, hatched and raised in captivity before being released into the wild – the survival chances go up to 30-50 per cent, Robertson said.

Intensive trapping, as well as the establishment of breeding programmes and pest-free areas, had also been a boon.

And the efforts to save the kiwi had flow-on effects for many other birds, with the reduction in predators helping other species to thrive as well, he said.

The number of animals in the “threatened – nationally critical” category dropped from 25 in 2012 to 18 in 2021, the report showed.

But it wasn’t all good news.

Only an estimated 30 tara iti/fairy terns remained in the wild, the report said, and two birds – the South Island pāteke/brown teal and the South Island kōkako – were classified as functionally extinct.