Only five percent of North Island brown kiwi chicks born each year survive until adulthood, according to a field study by Landcare Research scientist John McLennan. Unless 20% of kiwi chicks live to adulthood, the population will continue to decline, scientists say.

In the past 15 years the number of birds has plummeted from about 70 000 to 30 000.

Mr McLennan said the North Island brown kiwi was threatened by a growing number of predators and habitat loss. He also said there was insufficient funding to ensure its survival. Stoats, also known as ermine, head the list of predators, killing chicks within a month of their leaving the nest. Ferrets were also beginning to kill off remaining pockets of kiwi in Northland. The future is brighter for other species.

The populations of the great spotted kiwi and the southern brown kiwi are thought to be stable, although their ranges have diminished. The little spotted kiwi population is thought to number about 1 500 birds and is growing, thanks to island sanctuaries.

Mr McLennan, who has devoted most of his 15-year career to kiwi birds, said Northland kiwi were being killed off at about the same rate as kiwi in the lower North Island but because there were more of them, their decline would be slower.

- Sapa-AP