World's rarest kiwis
Kiwis are iconic in New Zealand, an integral part of the culture, appearing on merchandise everywhere, but in reality they have been disappearing in the wild. Now, the rarest of their kind, the rowi, is part of a long-running protection programme.
We visit the project that's aiming to save a national treasure in New Zealand
While he was growing up, Iain Graham’s family looked after a small cottage surrounded by native bush at the top of the Coromandel Peninsula on New Zealand’s North Island, which they would visit during the holidays. One evening as they sat around cooking on an open fire, Iain heard something snuffling through the undergrowth. He waited in silence for what he thought was a hedgehog – an introduced species – to appear from the lush ferns.
But when the source of the noise became visible it wasn’t a mammal at all: “A kiwi proceeded to feed around the fire at our feet,” says Iain. “I was fascinated by the way it slowly moved about, probing the ground seemingly unaware of our presence.” This unforgettable early experience shaped Iain’s passion for New Zealand’s endemic flora and fauna – today, he works as an officer for the Department of Conservation (DOC).
“Kiwis are a significant taonga (treasure) for New Zealanders, and are one of the most iconic creatures in the country,” says Iain. “If kiwis became extinct, we may have to change our national identity.” Not only have the birds become an affectionate nickname for New Zealanders, but they also feature widely across the media, advertising and in children’s literature, despite rarely being seen.
Dramatic decline
New Zealand has lost 90 per cent of its kiwi population in just 80 years: only 50,000 birds remain. This nocturnal animal soon got into trouble after the arrival of Maori more than 700 years ago. Habitat loss as a result of extensive burning and clearing of the forest, predation by domestic dogs, harvesting for food, and possible competition with introduced Polynesian rats led to extensive range reductions.
The rate of habitat destruction accelerated in the 18th and 19th centuries following European settlement, when forests became damaged by livestock and a new suite of terrestrial predators, including possums, stoats, cats and ferrets was unleashed on the avifauna that had evolved by their absence.
Since the publication of the first Kiwi Recovery Plan in 1991, complex conservation efforts have raised the profile of New Zealand’s kiwis and highlighted their dramatic decline. Rarest is the rowi, which has benefitted from a management programme called Operation Nest Egg (ONE). By 1995, they had come close to extinction with just 160 birds remaining, but 2018 figures show that the population has increased to 500 and its range has doubled. The IUCN recently downgraded its Red List status from Endangered to Vulnerable.
“Without management, more than 9 in 10 rowi chicks fall victim to mammalian predators.”
“Without management, more than nine in 10 rowi chicks fall victim to the jaws and claws of mammalian predators, so the remaining number in their small refuge start to decline as adult kiwis die through natural mortality,” explains Iain.
ONE has been running since 1996 and has been extremely successful in the conservation of rowi, which is found locally in coastal forest inland from Okarito on the west coast of South Island. Okarito Sanctuary was the last remaining refuge of rowi when the species was discovered in the early 1990s, so initial efforts were focused on this area to stabilise and then increase the population.
Common goal
The programme combines the efforts of DOC, community kiwi conservation groups, iwi (social units in Maori society), researchers and captive rearing facilities to quickly build kiwi populations, especially vulnerable populations at small sites.
“Early efforts saw between six and 12 juveniles being released into Okarito Sanctuary at the end of each breeding season,” says Iain. “Through our learnings and adoption of new technologies, we are now able to release 50-plus juveniles back into Okarito each season and start to expand the range.”
Rowi live in some of the thickest rainforest in the country and so finding them and visiting regularly requires conservationists to have high levels of fitness, as wildlife photographer Stefano Unterthiner discovered when he joined DOC ranger Tracey Dearlove in the 11,000ha Okarito Sanctuary to find one.
“The forest is dense and difficult to move through and the terrain is steep and undulating,” says Stefano. “It’s challenging for the rangers because once they collect the precious kiwi eggs, they must monitor them regularly on the way back to the West Coast Wildlife Centre (WCWC) in Franz Josef.”
Special encounter
Using radio telemetry, Stefano and Tracey found a tagged male guarding an egg in his burrow inside a tree trunk (it is more common for male kiwis to incubate eggs). “It wasn’t like any bird I’d seen before,” says Stefano. “It was a privilege to glimpse the world’s rarest kiwi.”
As Tracey removed the egg carefully and placed it in a warm, wool hat in an insulated container, the male remained in his burrow. “His mate could lay another egg in the same breeding season that will be collected again by DOC,” says the photographer. “If not, the pair will breed again the following year.”
Back at the West Coast Wildlife Centre, rowi eggs are incubated, hatched and stay for a month before moving to Willowbank Wildlife Reserve in Christchurch, which has more space and the facilities needed to rear the chick until it reaches 800g. “Their survival after release onto Motuara is significantly higher after this weight has been attained,” says Iain.
Motuara is the third stop for the young kiwis during this management programme. It is a predator-free island that is used as a crèche for rowi during the first year of their lives while they grow large enough to defend themselves at 1–1.2kg. Rowi don’t put on weight as quickly as other kiwi species, taking more than 12 months to become ‘stoat-proof’. The nocturnal birds are then released into Okarito Sanctuary where care is taken to avoid territory already occupied by adult pairs.
Though ONE was developed to bring kiwi back from the brink of extinction, the programme still has its challenges. “It costs a lot of money, which benefits only the single species that we are trying to manage and high numbers of chicks on crèche islands has brought about the need to vaccinate for diseases that wouldn’t occur naturally,” says Iain. “Even though the birds are living in the wild, they are treated as captive in their first year of life.”
Unanswered questions
On the plus side, ONE has allowed huge amounts of information to be collected on rowi as the birds are translocated, released and monitored at each stage of the process, so more can be learnt about the species and the best way to conserve it. This data is stored to answer questions on post-release survival rates and dispersal patterns, and to
compare management techniques. Today, not all rowi are monitored once they are released into Okarito. “As the population has grown the birds that are monitored have been selected depending on the genetics they contribute to the population,” says Iain. One hundred transmitters provide data on 60–70 breeding pairs. “By looking at genetic diversity, we have information to help establish satellite populations of rowi in new territories.”
Next steps
New Zealand’s third Kiwi Recovery Plan for 2017–27 aims to reach 100,000 kiwi by 2030 through growing populations of all kiwi species by two per cent per year, restoring their former distribution and maintaining their genetic diversity. The government has also set a goal to be free of introduced mammalian predators by 2050.
“Most managed kiwi populations are growing at rates of two per cent per annum or higher, however, the majority of kiwi remain unmanaged and are still in decline,” says Iain. “To tackle the target of growing populations of all kiwi, there will need to be an increase in the use and scale of in situ management of kiwi in the wild.”
Despite the success of halting the extinction of the rowi, only a small population of kiwi species receive any management. “The tools now exist to turn this decrease into an increase. In the next 10 years we will see kiwi conservation enter a phase of new growth for all species across the country,” says Iain. Kiwis are used as an indicator species in many ecosystem restoration projects because threats they face from introduced mammals are common with other native species. Saving kiwis could also mean saving the unique wildlife they represent. When the ferns rustle in the future, perhaps New Zealanders will expect to see an endemic bird, rather than a non-native mammal.
Rowi don’t put on weight quickly, taking more than 12 months to become ‘stoat-proof’.