By Annie Hill
The original article in Russell Lights | Ngā Mārama o Kororāreka, April 2026 edition
The first white settlers in Aotearoa, New Zealand, must have been singularly devoid of poetry to have named these sublime birds, ‘wattled crows’. Anything more different than a crow, which has drab, black plumage and a harsh, croaking voice, would be hard to imagine. While Kōkakoare are very rare now and confined to just a few places with intensive predator control, the hope of reintroducing them to the Russell Peninsula is one of the main inspirations behind the work of Predator Free Russell.
Kōkako, Callaeas wilsoni, is one of five species of New Zealand wattlebirds of the Callaeidae family, the others being two species of Tīeke Saddleback and the extinct Huia. They are among Aotearoa New Zealand’s most ancient flying birds, and their ancestors (which included the ancestor of the Stitchbird) may have been on the land mass that split from the super-continent of Gondwana to form our motu. However, their evolutionary relationship to other birds remains obscure.
There were two distinct species: the North Island Kōkako and the South Island Kōkako, but the latter is assumed to be extinct. Some hold out hopes that there may be remnant populations in remote forest areas, and there are more than a few reported sightings, but alas, what is remote to humans is easily accessible to rats, possums and stoats, which are the main vehicle of their demise. In this piece, I’m writing about the North Island Kōkako. Once widespread around the motu, the population was reduced to around 330 breeding pairs by 1999, but extensive pest control and a number of translocations resulted in a population of around 2,300 breeding pairs by 2023. However, Kōkako is one of the many species in this country that will not survive without human intervention, and any reduction in predator control would see them rapidly slide towards extinction again.
Kōkako are forest birds, although a healthy population is thriving among the young shrubs and trees on Tiritiri Matangi: as so often in nature, given a chance, a species will bounce back. Their home of choice is in tall, diverse native forest, with a canopy of Tawa or Taraire, along with podocarps or Kauri.
The Kōkako’s plumage is a beautiful, soft smoky grey, shading to brown on the long tail. They have a striking black mask from eye to eye, across their strong, down-curved beak. Their most distinctive feature is a bright blue wattle under each eye (orange on the South Island birds: a few North Island birds also have an orange wattle). Like their cousins, Tīeke Saddleback, they’re poor fliers, with short and rounded wings, used more for gliding than flying: indeed, they’re incapable of flying more than about 100m. Instead, they have long, muscular legs and move by bounding from branch to branch, while also happily spending time on the forest floor. This means that it’s absolutely crucial that attempts at reintroduction ensure that the eradication of predators goes hand in hand with the restoration of forest corridors.
Kōkako are renowned for their song, which is haunting and ethereal. Sometimes described as organ-like, the notes are supremely clear, like those produced from running a wet finger around a glass. More often heard than seen, they’re known as ‘grey ghosts’. Pairs sing together, particularly in the morning: their slow-paced duet, sometimes audible from several kilometres away, can last for an hour, reinforcing their bond and claiming their territory. Different populations of Kōkako exhibit distinct song dialects, which reflect their territorial nature and the cultural transmission of song. Apparently, new arrivals on Kapiti were slower in establishing pairs than was expected, because female birds preferred a mate from the same area of origin. In stable territories, adults are not known to change their repertoire once they’ve learnt it, but over time, the birds on Kāpiti learnt to add or delete notes to fit in with the other birds.
The diet of Kōkako consists largely of fruit, fern fronds and leaves and, less often, flowers, moss, buds, nectar and invertebrates; the latter are probably more important when feeding their chicks. They often use one of their feet to hold food while consuming it.
Monogamous, Kōkako hold territories as a pair and stay together outside the breeding season. They build a cup-shaped nest of vegetation, placed on a large twig platform and lined with tree-fern scales, although they occasionally make a scrape on a suitable epiphyte, again lined with tree-fern scales. While nests tend to be high up in trees, occasionally they’re only a couple of metres from the ground.
Generally, the female just lays one clutch of two to three eggs each year, but when food is abundant, a pair can raise up to three broods of chicks. The female alone incubates the eggs for 18 days, during which time the male feeds her. The chicks take a long time to fledge, up to 42 days, and the female is very vulnerable during this time. Relic populations, in areas without predator control, are predominantly male because of this, with studies showing that for every 10 breeding pairs, just one chick per year survives. The juveniles are also dependent for a long time – from several months up to a year – during which time both parents provide food. Young birds usually breed from 1 to 2 years old, and they can possibly live up to 20 years.
As well as the usual suspects, a big threat to Kōkako comes from deforestation, leading to isolation. A minimum size for a viable population is around 40 breeding pairs, which need a sizeable area of good-quality forest for their territories, which range from 4 to 25 ha. Possums, as well as stealing eggs and chicks, also compete directly with Kōkako for food, as do goats and deer, grazing on the understorey. They’re also vulnerable to Harriers while on the nest, especially where a lack of habitat might force a pair to nest at the edge of woodland.
In Māori tradition, Kōkako used his wattles to carry water to the demigod Māui when he grew thirsty in his battle against the sun. Māui rewarded the bird by making his legs long and slender so he could move easily through the forest. It would be glorious if one day these birds were once more living around Russell.
Kokāko | Callaeas
📸 Credit: Darren Markin