The first hihi, or stitchbirds, to hatch on the Auckland mainland for more than a century are emerging from their nests in the northern Waitakere Ranges as they prepare for flight.
The first signs of the fledgling chicks have excited those involved in the Ark in the Park Project, a Forest and Bird and Auckland Regional Council restoration project in the Cascades Kauri Park.
The project, which includes the work of volunteers, aims to reintroduce native animals and plants that had become extinct in the Waitakere Ranges.
Sandra Jack, manager of Ark in the Park Project, said the volunteers had been hungry for news about the nests.
"The fledgling is yet another stage in the process of hihi establishing in the ranges. There are still chicks in the nest being fed by dad but they will no doubt fledge very soon too."
Ms Jack said the females were off re-nesting to lay and incubate new clutches of eggs.
The first fledgling hihi to be spotted was in a nest 30m off the ground, the highest hihi nest ever recorded, and in a kauri tree, which is also unusual.
Hihi are one of New Zealand's rarest birds but they were once found throughout the North Island until introduced predators and habitat destruction reduced their distribution to Hauturu/Little Barrier Island.
Last month the first hihi were hatched in the Waitakere Ranges after 59 were transferred from Tiritiri Matangi Island.
The population is gradually expanding on the Hauraki Gulf island but at least half the young produced each year died of starvation due to the shortage of mature forest habitat.
The transfer followed an intensive programme of pest control so the birds were more likely to survive on the mainland without being preyed on by introduced pests such as possums, rats and stoats.
About 10 birds were thought to be still living in the Waitakere Ranges, the first time hihi had lived on the Auckland mainland since their populations were wiped out in the late 1800s.
Ms Jack said the fledgling hihi chicks looked like overgrown sparrows but the males would soon develop their distinctive markings. They have a black head and white ear tufts, bright yellow shoulders and breast band and a white wing bar.
Females were smaller with more sombre olive to grey-brown colouring.
Ms Jack did not know how many chicks had been hatched or made it to fledgling.
Even finding the adults was a challenge, she said.
Hihi had a distinct upright tail posture which usually set them apart from other native species.
They also had large, bright eyes and long cat-like whiskers around the base of their necks.
The birds could be readily detected in dense forest by their strident call, which has been likened to the word stitch or two stones being repeatedly struck together.
Hihi also had a low warbling song that can last several minutes.
The birds fed predominantly on nectar, but also ate insects, particularly in the breeding season.
Feeding stations would be built in the park near walking tracks so visitors could encounter hihi more readily.