Kōkako numbers in the Ōtanewainuku forest have increased by 15 since 2018 according to the latest survey conducted recently by the Ōtanewainuku Kiwi Trust.
Trust chairman Bruce Fraser said teams of volunteers under the guidance of kōkako experts spent two weeks in the forest spotting birds and recording territories.
"Before the impact of pests and predators, kōkako flourished in Ōtanewainuku. But by the early 2000s there were no kōkako left. However, with excellent pest and predator control, we have been able to reintroduce kōkako into Ōtanewainuku.
''We are very grateful to the Rotoehu Ecological Trust, the Kaharoa Kōkako Trust and the support of six local iwi for the 39 birds we have translocated into Ōtanewainuku.
''This result is in line with previous surveys and gives us a cautious confidence that we will once again see kōkako flourishing throughout the Ōtanewainuku forest and beyond.''
With the introduced birds and natural breeding numbers were up to 52 in 2018 and there are now 31 pairs and seven single birds were counted in the latest survey bringing the total up to 69.
"Volunteers are the driving force of the work the trust does to protect kiwi, kōkako and other animals and plants of the forest and this project was no exception with over 750 volunteer hours recorded so far with more to come tidying up reports.
''Survey co-ordinator Hans Pendergrast in particular spent many hours organising the work and the volunteer teams and we're very grateful for his input."
Hans said it's such a privilege to be involved in the recovery plan for kōkako.
"The national recovery plan objective is to reach 3000 pairs by 2025. This survey result for Ōtanewainuku has added value to the recovery plan. It's so exciting to see kōkako pairs establishing territories in new areas within Ōtanewainuku.
''I continue to marvel at the skill and commitment of the kōkako experts who lead the work in the forest. The enthusiasm and commitment of our trust volunteers made the survey work efficient, created an excellent team spirit and added knowledge and experience to our volunteer capability.
''There's still much to do to control pests and predators, but the hard work is so worthwhile when we see the kōkako population continue to flourish," Hans said.
The kōkako belongs to the endemic New Zealand wattlebirds (Callaeidae), an ancient family of birds which includes the saddleback and the extinct huia.
The kōkako is the only member of its family to have survived on the mainland.
It has a pair of brightly coloured, fleshy wattles extending from either side of its gape to meet below the neck. The bird is not particularly good at flying and prefers to use its powerful legs to leap and run through the forest.
The next survey will be conducted in 2024.