The recovery of Northland's grey-faced petrel population has been enhanced with the fledging of five chicks at Whangārei's Bream Head.
Bream Head Conservation Trust can add another feather to its cap with the successful breeding.
By flexing their wings and flying away, five grey-faced petrel chicks have created another trust success story following years of heartbreaking chick losses.
Since 2002 when the Trust began restoring habitat on the pest-ridden Bream Head Scenic Reserve at the tip of the Whangārei Heads Peninsula, there have been a number of conservation victories.
"It brings hope that other seabird species may return to Bream Head to breed."
They include self reintroduction by native bird species such as kaka, discovery of a new skink species and translocation of North Island robin and whitehead populations.
This summer, for the second successive year and after decades of absence from the reserve, 100 per cent of grey-faced petrel chicks have successfully fledged from their burrows on the eastern face of Bream Head.
Their survival is the result of a hard-hitting predator control and monitoring programme developed in response to loss of chicks to predators in previous seasons.
"The Trust is excited to have protected a second season of grey-faced petrel adults and chicks to the stage where the chicks were able to fledge," chairman Greg Innes said.
"It brings hope that other seabird species may return to Bream Head to breed, and that the pest control and monitoring model we used will now prove useful for other mainland sites working to restore sensitive bird species and bring about a predator-free New Zealand."
Trust ranger and project manager Adam Willetts said the grey-faced petrels returned to breed at Bream Head in the 2015/2016 season, one of only a few known, naturally occurring mainland breeding sites for the large grey seabirds.
Known to Māori as oi, they hadn't been seen on the reserve for decades after humans and animal predators wiped them out.
"Ten chicks fledged last season, and this year our infra-red camera monitoring, burrow searches and intensive predator control showed all five chicks in our study area had fledged," Willetts said.
"That is two seasons, back-to-back, with 100 per cent chick fledgling success after two years of having chicks killed by stoats when close to fledging."
Extensive video monitoring has allowed Willetts and the other rangers to witness the petrel chicks exiting the burrows, exercising their wings and removing down feathers before taking their fledging flights.
"We then checked all monitoring data and used a burrow scope to investigate chick chambers and entrance tunnels before being able to confirm they were empty."