Possibly heard, and maybe seen, the search for the South Island Kōkako continues

Beneath the beech trees and broad leaves that cloak the western regions of New Zealand’s South Island, a small team of devoted ecologists and volunteers battle on in their search for the enigmatic South Island Kōkako (Callaeas cinereus). It is perhaps not so surprising that these staunch believers refuse to give up on the forest-dwelling bird, which has beautiful slate-gray feathers and majestic orange ornaments, called wattles, that hang tightly on either side of its beak.

It is more than just hopeful imagination that fuels their campaign. Glimpses of kōkako-like creatures seen from afar have been reported dozens of times–as well as reports of encounters in recent years–and recordings of an unusual bird call with rich flute and organ notes cutting through the more familiar songs of Tūī and Bellbirds are tantalizing clues suggesting that the South Island Kōako is still out there.

“The South Island Kōkako is one of New Zealand’s most remarkable but almost entirely forgotten rare birds and the most beautiful part of the original dawn chorus,” says Inger Perkins, General Manager at the South Island Kōkako Charitable Trust, a small organization that was set up just over a decade ago to find and save the species from extinction.

Today, the South Island Kōkako is one of the top 25 most wanted by the Search for Lost Species which aims to rediscover animals, plants and fungi that have not had a documented sighting in 10 years or more. The initiative collaborates with experts from the IUCN Species Survival Commission to source nominations for species that meet the criteria of “lost to science.”

“You don't want to declare something extinct that could still be saved, because every single organism in an ecosystem plays an important role,” says Christina Biggs who is the lost species officer at Re:wild.

Sadly, the haunting melody of the South Island Kōkako’s call is not the only bird call that has faded from New Zealand’s forests. Once rich in bird life, 82% of New Zealand’s bird species are at risk of extinction, largely due to predation by rats, stoats, ferrets, possums and feral cats that have been brought to the island-nation by humans.

The last officially accepted sighting of a South Island Kōkako was in 2007 near Reefton on the west coast of South Island. Before that, a bird was seen near Makarora in Mount Aspiring National Park in 1967. The species was declared Extinct by the New Zealand Department of Conservation in 2008 and then bumped to a Data Deficient status in 2013, in light of the 2007 sighting. Now, the species is classified as Critically Endangered by the IUCN Red List of Threatened Species.

There are no known photos of the South Island Kōkako nor confirmed recordings of its call, which has made it especially hard to determine its whereabouts. In response to this lack of data, the South Island Kōkako Charitable Trust launched a $10,000 NZD prize in 2017 for anyone able to provide photographic evidence of the species.

"Our public campaign aims to encourage all backcountry users, including hunters, birders, climbers, trappers and others, to join the search," says Perkins. “The search for our kōkako follows in the tradition of the Kakāpō, Black Robin, Takahē, Chatham Island Taiko and the recovery of many other critically threatened species.”

During the first half of 2023, a team of volunteers led by retired ecological consultant and former New Zealand Wildlife Service employee, Rhys Buckingham, set out on a series of four expeditions to search for signs of the elusive bird, continuing Buckingham’s life-long mission to find the species since he first heard its mesmerizing call back in 1977.

The crew ventured into a hotspot for possible kōkako encounters that is located around a stream called Evans Creek and the Falls River in central Abel Tasman National Park. Another team of volunteers examined sites in the Kahurangi National Park. By placing multiple cameras and acoustic recorders at the various sites, and playing the calls of the North Island Kōkako–which resembles those of the southern species and looks very similar except with a blue wattle–the team looked to provoke and capture responses from any hiding South Island Kōkako.

Several days went by with no signs of the kōkako. Then, on the final morning of their first expedition in early April, two of the crew heard promising calls. The notes sounded as if they were coming from two kōkako, one in an upper valley region and another further down the valley.

“Initially, both observers were together when they heard a double note call suspiciously like a loud kōkako call, nothing like calls they had heard the week beforehand,” Buckingham wrote in a report.

Spurred on by these tantalizing accounts, Rhys revisited the same region in May, again playing out calls of the North Island Kōkako. “The weather was calm, misty, damp but mild–conditions when North Island Kōkako are often conspicuously vocal,” Buckingham wrote of the trip.

He found more hopeful evidence. “At one point it appeared that three anomaly birds called from three different directions…The unidentified birds making calls like kōkako appeared to be reluctant to approach more than an estimated 50 meters [165 feet] from the observer.”

The riveting recordings are now being analyzed by professor Stephan Marsland, a mathematician at the Victoria University of Wellington. This will help to determine whether the calls are likely from the South Island Kōkako or simply sounds made by other bird species that learned the kōkako’s legendary call– perhaps recently or perhaps years ago before passing it down through generations.

“[Marsland] has created a filter that he hopes will isolate calls that could be a Kōkako,” says Perkins. “We know that Tūī birds can mimic other bird calls and we know that the Kākā has a very similar soft note [compared to the kōkako] in its more usual squawky repertoire. We’re hoping that the [sound graphs] will be different enough, for example, the notes of the Kōkako may slide between notes, whereas those of the Tūī might step between the notes.”

Beyond recording birdsongs, the team have also tried tracking down kōkako by scanning the ground for potential kōkako feathers and searching for evidence of one of the kōkako’s assumed feeding strategies, known as moss grubbing, which involves neatly cutting out circles of moss to search for grubs to eat. However, they haven’t had any luck finding feathers or moss grubbing yet at the sites in Abel Tasman National Park and Kahurangi National Park. If promising feathers are found during future expeditions, they will be sent for DNA sequencing to check whether they belong to the kōkako, says Perkins.

South Island Kōkako Charitable Trust is also working with the University of Otago, a DNA lab and volunteers on the application of environmental DNA, finding the best way to confirm the presence of North Island Kōkako by sampling water, mud or even air for analysis, before it can be applied in areas where the cryptic South Island kōkako may be hiding.

Although the South Island Kōkako Charitable Trust hasn’t found conclusive evidence of a South Island Kōkako yet, Biggs says that mounting such a thorough search makes her hopeful that the elusive bird could still be found.

“I find it heartening that people continue to look because they, in their very being, want to know that these animals are okay and will be protected in the future,” says Biggs.

The search for the South Island Kōkako is supported by Allbirds.