A claimed sighting of the South Island kokako, a bird declared extinct six years ago, has fuelled hopes the species could still be alive.
Advocacy group Forest and Bird said a sighting of the bird by two people near Reefton in 2007 had recently been accepted by the Ornithological Society's Records Appraisal Committee, which monitors the status of rare and endangered birds.
Before the Reefton sighting, the last accepted sighting of a South Island kokako was in 1967.
Te Ara Encyclopaedia of New Zealand says the kokako's haunting, evocative call is unlike any other bird's.
Maori legend has it that the kokako's long, lean legs were a gift from Maui after the bird filled its wattles with water to quench Maui's thirst as he fought the sun.
The Reefton sighting was one of 11 such sightings submitted, but the others - from the Marlborough Sounds, northwest Nelson, the West Coast and the Catlins, between 1990 and 2008 - were considered to be only only "possible" or "probable".
An expert panel convened to manage the New Zealand Threat Classification System (NZTCS) earlier this month changed the South Island kokako's classification from "extinct"' to "data deficient", based on the 11 claimed sightings.
Forest and Bird advocacy manager Kevin Hackwell said that while it couldn't be confirmed the South Island kokako was still alive, "this is the best sign yet that it is".
"Sadly, when the claimed Reefton sighting was made, the area was subject to intensive pest control. But that pest control stopped several years ago," he said.
"Because of the reclassification, there needs to be more pest control work in the South Island than ever before.
"If they are still out there, the South Island kokako will just be hanging on, and their biggest threats will be rats, stoats and possums.
"New Zealand is thought to have lost over 50 bird species. If just one of those extinctions turns out not to have happened, it would be incredibly good news."
Forest and Bird member Alec Milne, who claims to have heard and seen South Island kokako, and runs a project to find evidence they still exist, described the Ornithological Society's decision as "wonderful".
The birds have - or had - orange wattles on their faces. The endangered North Island kokako has blue wattles.