Kokakos: Characteristics, Behavior and Reproduction | Sea Life, Islands and Oceania

Home | Category: Nature, Environment, Animals

KOKAKOS

drawing from 1883 of North Island kokako with blue wattle in front and a South Island kokako with orange wattle in back

Kōkakos are two species of forest bird in the genus Callaeas which are endemic to New Zealand: the endangered North Island kōkako (Callaeas wilsoni) and the presumed extinct South Island kōkako (Callaeas cinereus). The last documented sighting of South Island kokakos was in 1967. Both species are slate-grey with colored wattles and have black masks. They belong to a family containing five species of New Zealand wattlebirds, the other three being two species of tīeke (saddleback) and the extinct huia. Kokados found on the South Island had a deep orange wattle, while those on the Norther Island is cobalt blue. [Source: Wikipedia]

There are no squirrels in New Zealand. The niche normally occupied by squirrels is taken by kokako. About the size of pigeons, kokako can fly but prefers to scamper along tree branches. They use their wings mainly for balance when they jump from branch to branch in search of fruit and insects. When they do fly they don't flap their wings but glide like flying squirrels.

Previously widespread throughout New Zealand, kōkako populations have been decimated by invasive species such as possums, stoats, cats and rats, and their range has shrunk significantly. In the past, kokako were called the New Zealand crows. They are not closely related to crows at all, but look like them from a distance.

Kokakos are now reduced to 15 populations in the mainland’s northern and central forests. Some also naturally occur on islands 50 kilometers from the North Island mainland. The estimated total amount of adult kokakos in 2010 was 1,538 adults, 769 of which were breeding pairs. Translocation programs from 1990 to 1997 took individuals from several different populations on the North Island mainland to Kapiti Island and the southern portion of the North Island. [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]

Kokakos are found on the Northern Island of New Zealand in rainforests and areas with specific hardwoods, such as podocarps, and a variety of shrubs at elevations of two to 38 meters (6.56 to 124.67 feet) at an average elevation of 13 meters (42.65 feet). Their nests are primarily found in wooded gullies and ridges built towards the top of trees, well covered by canopy. When foraging for food, kokakos stay primarily in the canopy and the upper understory.

Kokako Characteristics

North Island kokako

Kokakos are medium size birds. They range in weight from 210 to 245 grams (7.40 to 8.63 ounces), with their average weight being 219 grams (7.72 ounces) They have a head and body length of 38 to 50 centimeters (14.96 to 19.69 inches). Their wingspan ranges from 50.2 to 52.1 centimeters (19.76 to 20.51 inches). Sexual Dimorphism (differences between males and females) is present: Both sexes are roughly equal in size and look similar but males are a little larger and ornamentation is little different. [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]|=|

Kokakos feathers are blue-grey in color, the beak, legs, and face mask are black. The beak is round and short, and the legs are long and slender. Wings are short and round contributing to its limited flight capability. Directly under the beak is a cobalt blue wattle; a soft mass of tissue. The wattle om the extinct South Island species was orange. Adult wattles vary in the brightness and hue depending on the age and condition of the individual bird. Kokakos are relatively long-lived species. It is estimated that their average lifespan in the wild is 11 years. |=|

Kokakos are omnivores (eat a variety of things, including plants and animals). Animal foods include insects and other arthropods. Among the plant foods they eat are leaves, buds, fruit and flowers. Diet and the amount of time spent feeding varies according to season. More time is spent foraging during autumn and winter and less during the spring and summer. The amount of sixpenny scale insects (Ctenochiton viridis)increases sharply during the spring when they make up the majority of kokakos' diets. Kokako eating habits also vary year-to-year according to region. In one study, three sample forest areas yielded more than 100 different food items eaten by kokakos. The greatest portion of kokakos' diets was composed of fruit followed by the leaves of dicotyledonous shrub and tree species within their habitats, particularly the fruit and leaves of raukawa, fivefinger, tawa, and rearewa. A smaller proportaion was made of, flowers, buds, sixpenny scale insects and gymnosperm cones.

Kokako Behavior, Senses and Communication

Kokakos are arboreal (live mainly in trees), scansorial (good at climbing), diurnal (active during the daytime), crepuscular (active at dawn and dusk), motile (move around as opposed to being stationary), sedentary (remain in the same area) and territorial (defend an area within the home range). They can fly but are not great fliers and tend to fly only short distances to get from one branch to another or in an emergency. Their home territories range from four to 14 hectares (9.9 acres to 34.6 acres) [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]

South island kokako (extinct one) range: the estimated historical distribution along with the last two generally accepted sightings; two distributions are shown: the estimated maximum extent of the kōkako (greyish-green) based on fossil records, and the estimated extent by the period of European settlement (green) based on settler records; The 1967 sighting is often regarded to be the last accurate sighting of a South Island kōkako in the 20th century; The 2007 sighting has been accepted by the Ornithological Society of New Zealand (OSNZ) Records Appraisal Committee

Kokakos spend most of their time in the canopy and the upper understory of the forests they inhabit. They only socialize with neighbors to establish territory and pair-bonds during the dawn chorus. Other than songs, socialization is limited to a single pair-bond within a territory. Kokakos are very territorial and generally stay within the same area year round, for many years. Activity takes place during the day and especially dawn. Some describe the personality of kokakos as crowlike — shy, inquisitive, and crafty — while others say they are gentle, kind, and unafraid of human interaction.

Kokakos spend most of their lives feeding, nesting, and defending territories at 5.5 to 20.5 meters (18 to 67 feet) above the ground within the layers of canopy, but can also be found on the forest floor. To return to the tree tops from ground level, kokakos run up the trunk of the tree directly from the bottom — a technique called ‘squirling’. Due its limited capabilities of flight, kokakos rely on their long slender legs to get around — hopping from place to place, spreading their tail and wings slightly for balance.

Kokakos communicate with vision and sound and employ duets (joint displays, usually between mates, and usually with highly-coordinated sounds) and choruses (joint displays, usually with sounds, by individuals of the same or different species) to communicate. They sense using vision, touch, sound and chemicals usually detected with smell. [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]

Kokakos communicate to other kokakos with an organ-like song, which the Maori describe as a haunting“Te Koha Waiata” (“gift song”). Call phrasing is not sexually specific and can be observed in both pair-bonds and singular birds to express territorial defense. Their calls are antiphonic duets — duets in which one bird begins a phrase and after a pause the other ends it, with alternating male and female contributions to the song. Kokakos can distinguish between single birds and pair-bonds based on the gap between calls. As territory is protected year round, the calls advertise where a territory is to neighbors, decreasing the likelihood of territory invasion and confrontation. If a pair-bond inhabits a territory they advertise the fact with their chorus. Kokakos songs are also involved in mating, with female’s mate choice at least partly affected by the phrase type of a male’s song. There are at least 18 different phrases in a kokako’s song, 86 percent of which are locally unique to each population. Given the choice, a female picks a male from the same population in which she originated.

During the dawn chorus both bonded pairs and single kokakos perch at the top of tall trees, usually a podocarp, within their territory and perform their duet or single song. The tall perch allows the birds to see their neighbors and enables them to be heard better.

Kokako Mating and Reproduction

range of North Island kokako

Kokakos are monogamous (have one mate at a time) and Mating-pairs usually stay together for many years.. They engage in seasonal breeding and have been known to breed up to five times within one, annual breeding season. The breeding season runs on average from October to March. Some ‘good’ seasons can extend six months after that. ‘Good’ and ‘bad’ seasons seem be a correlated with fruit availability, which makes up a large portion of kokakos' diets. The number of eggs laid each season ranges from three to nine. The average time to hatching is 18 days. [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]

Kokakos find, attract, and defend mates with songs. Females begin recruiting a pair-bond mate one to two years of age; males do so at two to four years of age. Pair-bonding is not restricted to male and female pairs. There are also female-female and male-male ones. Female-female pair-bonds share a territory for a short period of time, and attempt to mate at least once per season. These bonds are not so common and have not been recorded recently, perhaps due to increasing predation of nesting females by invasive rats, cats and stoats. In contrast, male-male pair-bonds are more common. Many experts believe that this is a recent phenomenon that is a direct result of a shortage of female, but others speculate that juvenile males choose a same sex bond even when are females are more plentiful.

Both the male and female are active in territorial protection and year round courtship rituals, including preening at the base of the beak and offerings of food to the female by the male. Kokakos sexual selection is based on female choice. Females have been known to visit the territories of up to nine different unpaired males before deciding on a mate. At first, a female is drawn to a male’s territory by the phrasing of his song, but a final choice is made based on the quality of resources within the territory and the body size, color of plumage and overall health of the male. A male proves his physical health to the female by performing an “archangel” display, in which he lowers his head, extends his wings, and vigorously runs along branches near the female. During this display males are known to have leaves or twigs in their beak. Both the male and the female take part in mate guarding. Kokakos' antiphonic duets convey pair identity, the length of their bond and their relationship with birds in neighboring territories.

Once a mating pair is established in a territory, nesting and reproduction begins. During a mating season kokakos have been known to attempt breeding up to five times. In the event of a nest failure, due to predation or infertile eggs, the female can begin to re-nest within four to five weeks. In a successful season a pair has been known to fledge three clutches, each clutch containing an average of two eggs, at most three, which are laid at a one day interval. The average output of fledged offspring per season is six, assuming it is a ‘good’ season. In the event of a ‘bad’ season the youngest chick, which was laid last, usually does not fledge. Once laid, the eggs are incubated for 18 days.

Kokako Nesting, Offspring and Parenting

Parental care is provided mostly by females but males are involved. During the pre-fertilization stage provisioning and protecting are done by females. During the pre-birth, pre-weaning and pre-independence stage provisioning and protecting are done by males and females. Before fertilization, females build the nest almost completely on their own. Male does offer token help by presenting some twigs and foliage to the female for nest building, while performing their ‘archangel’ display. Male kokakos are quite capable of building a nests. It is common for males in male-male pair-bonds to do so. The nest is an untidy, bowl-shaped, mass with twig base, and made of entwined moss, lichens, ferns, treefern scales, epiphytic orchids, and dead wood. It can be anywhere from two to 32 meters above the ground. The longest recorded time for nest construction is 11 days; usually it takes two to five days. When nest-building begins females randomly gather bits and pieces, spending very little time, but as the time to egg-laying nears female becomes more focused on nest construction. [Source: Sarah Harrison, Animal Diversity Web (ADW) |=|]

Kokako eggs are oval-shaped and pink-grey in color, with brown and purple streaks and spots. They are 3.3 to 4.4 centimeters in length, 2.3 to 2.8 centimeters in width, and weigh 14 to 16 grams. Young kokakos have dull brown-green coloring on the majority of their feathers except for their abdomens and under their tails, which are yellow-brown. A nestling’s wattle is pink when first hatched and becomes pale blue with age. There is little distinction between males and females, both possessing the same patterns and colors.

Young are altricial, meaning they are relatively underdeveloped at birth. Their eyes are closed, they have no feathers, and only limited movement when they are born and rely entirely on their parents for the first month and a half of life. During the first ten days of the chick’s life they grow at a rate of 10 grams per day. The chicks stay in the nest for a period of 34 to more than 42 days before fledging, and after fledging stay with their parents until they are 10 to 12 weeks old. Before fledging, both the male and the female parents take part in feeding young, foraging with one another. Food for the chicks is brought back to the nest in the beak and throat. |=|

Before hatching, females and eggs are most vulnerable to predation. Nests are well off the ground and generally well hidden from areal predators by the thick canopy, but are defenseless against introduced, tree-climbing predators, such as possums. When a nest is threatened by native birds of prey such as Australasain harriers and New Zealand falcons, a nesting pair of kokados flee the nest and hide and delay returning until it is safe to come back or desert the nest completely. In the event of a possum threat males hide and delay returning, while females either hide with the male or stay on the nest, often becoming prey along with the eggs. When a nest is threatened by cuckoos, kokakos physical attack the invading birds. |=|

Parental Investment is reduced as the brood becomes more independent. Some parents allow their offspring to stay in their territory and continue to supply them with food, while others attempt to drive offspring away even before fledging. During the nesting and post-fledging period chicks become familiar with and learn localized song phrasing, leading to later mate choice. When juveniles finally leave the nest they begin to search for a territory of their own, and despite their limited powers of flight, travel reasonably long distances until they settle on a specific area. In one study, juvenile kokakos in the Rotoehu forest travel on average 1.45 kilometers in search of a suitable territory.

Kokakos, Humans and Conservation

North Island kokakos have been listed as a species of Least Concern on the International Union for Conservation of Nature (IUCN) Red List since 2022. Before they were listed "Near Threatened". The South Island kokako is listed by the IUCN as Critically Endangered in 2019 and is likely or possibly extinct, with most recent reported sightings unconfirmed. [Source: Google AI]

There were over 2,300 North Island kōkako breeding pairs as of 2023, representing a significant increase thanks to conservation efforts. Large populations are found in Pureora Forest, Little Barrier Island (Hauturu), and the Hunua Ranges. Recovery is attributed to ongoing pest control and the translocation of birds to new sites.

One of the main species targeted for pest control that affects kokakos is Australian bush tail possums. prey mainly on eggs, chicks, juveniles, and nesting females. Habitat loss and degradation has also been an issue. The destruction of habitat by logging has left only 10 percent of kokakos' original native habitat.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org , National Geographic, Live Science, Natural History magazine, David Attenborough books, New Zealand Geographic, New Zealand Tourism, New Zealand Herald, Te Ara Encyclopedia of New Zealand, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The Conversation, The New Yorker, Time, BBC, CNN, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian and various books, websites and other publications

Last updated September 2025