Callaeas cinereus, commonly known as kōkakos, is endemic to New Zealand. Kōkakos were historically found in abundance through out the North Island, but are now reduced to 15 populations, concentrated in the mainland’s northern and central forests. Populations can also naturally be found on islands 50 km from the North Island mainland. The estimated total amount of adult kōkakos as of 2010 was 1,538 adults, 769 of which were breeding pairs. In an effort of conservation, translocation programs from 1990 to 1997 have taken individuals from several different populations on the North Island mainland to Kapiti Island and the southern portion of the North Island.
Biogeographic Regions: oceanic islands (Native )
Other Geographic Terms: island endemic
Kōkakos communicate to others of its species by an organ-like song. The native people of New Zealand, the Maori, call its haunting and unique song, “Te Koha Waiata”, translated as “the gift song”. Call phrasing is not sexually specific and can be observed in both pair-bonds and singular birds as a means of territorial defense, and is referred to as an antiphonic duet. An antiphonic duet is when one bird begins a phrase and after a pause the other ends it, alternating male and female contribution to the song. Kōkakos can distinguish between a single bird and a pair-bond by their ability to detect the spatial gap between the pair. Because territory is guarded year round, this duet behavior advertises that there are two protecting the territory to their surrounding neighbors, decreasing the likelihood of territory invasion and confrontation. A population of kōkakos will let their neighbors know where their territory is and if a pair-bond inhabits it by joining in a chorus, in which the surrounding population sings together at dawn. The defense of a territory or mate is not the only purpose for kōkakos' songs. One contributing factor to a female’s mate choice is the phrase type of the male’s song. There are 18 different phrases in a kōkako’s song, 86% of which are locally unique to each population. Given the choice, a female will pick a male from the same population in which she originated. Like most birds, kōkakos perceive their environments through visual, auditory, tactile and chemical stimuli.
Communication Channels: visual ; acoustic
Other Communication Modes: duets ; choruses
Perception Channels: visual ; tactile ; acoustic ; chemical
Kōkakos were listed as an endangered species by 1994 and this status has not changed since. There are several reasons for the endangerment of kōkakos. The destruction of habitat by logging has left only 10% of kokakos' original native habitat, reducing territorial area available to juveniles and lowering food availability. The mammalian predators introduced to New Zealand by European settlers in the 1800s prey mainly on eggs, chicks, juveniles, and nesting females. The large numbers of mammalian predators have decreased fledging success. In the years during pest management 61% of birds fledged, while in years of no management the number was reduced to 29%. The female population of kōkakos has also been altered, leaving a large surplus of male-male bonds, which do not produce offspring. The introduction of browsing mammals, such as possums, goats, and deer, has caused food competition with kōkakos, and is also believed to play a role in the decline of kōkako populations.
CITES: no special status
IUCN Red List of Threatened Species: no special status
Kōkakos have no known negative effects on the economy.
In the process of kōkakos conservation efforts an onslaught on introduced mammalian predators has been implicated by areal poisoning and ground trapping. One of the main species targeted for pest control that affects kōkakos is Australian bush tail possums (Trichosurus vulpecula). Possums were introduced to New Zealand in the 1800s by colonizing Europeans to create a base for fur trading. Possums have become so well-adapted to the island that their numbers are now in the millions, which not only affects kōkakos' already dwindling numbers, but the local establishment of farmed cattle and deer. Farmed cattle and deer are of great economic importance to the people of New Zealand and the possum carries a strain of bovine tuberculosis that can infect both cattle and deer. Controlling the population of possums for kōkakos benefits the population size and lowers the chance of infecting local farms. Because kōkakos can only be found in New Zealand, ecotourism contributes to economic growth.
Fruit makes up the largest portion of kōkakos' diets. Small fruits of a variety of plant species are consumed whole, allowing for the opportunity for seed dispersal. However, due to decreasing population numbers, poor flight capabilities, and stationary territorial lifestyles, kōkakos do not likely have a large ecological effect on the dispersal of seeds. This is also true regarding browsing and the defoliation of plants. Sixpenny scale insects, an important food source for kōkakos during spring months, live on the undersides of leaves and the leaves are systematically picked off. A pair of kōkakos was observed detatching 60 leaves in a 20 minute period. It is believed that when kōkakos flourished throughout New Zealand, before European settlement, it may have had a larger ecological effect on seed dispersal, browsing, and defoliation.
kōkakos' food habits vary from year-to-year, by season, and territory. In general they are omnivorous and feed on fruit, foliage, insects, flowers, and buds. In one study, three sample forest areas yielded more than 100 different food items eaten by kōkakos, reflecting the local ecology. The greatest portion of kōkakos' diets was composed of fruit followed by the leaves of dicotyledonous shrub and tree species within their territorial areas. This included, but was not limited to, the fruit and leaves of raukawa, fivefinger, tawa, and rearewa. A smaller contribution to kōkakos' diets includes sixpenny scale insects (Ctenochiton viridis), flowers, buds, and gymnosperm cones, respectfully, from greatest contribution to smallest.
The amount of time spent feeding varies, along with diet, from season to season. Less time is spent foraging during spring and summer months and is increased greatly from autumn to winter. The greatest amount of time spent feeding occurs during the winter months, even with the decrease in day length. The amount of sixpenny scale insects consumed is relatively low during much of the year, in exception to the spring months when these invertebrates encompass the majority of kōkakos' diets.
Animal Foods: insects
Plant Foods: leaves; fruit; flowers
Primary Diet: omnivore
Kōkakos are found on the Northern Island of New Zealand in areas with specific hardwoods, such as podocarps, and a variety of shrubs. Their nests are primarily found in wooded gullies and ridges built towards the top of trees, well covered by canopy. When foraging for food, kōkakos stay primarily in the canopy and the upper understory. Kōkakos are territorial, and therefore require far reaching forests to accommodate. Territories vary in size depending on the region that is occupied, but on average live in territories of 4 to 12 ha.
Range elevation: 2 to 38 m.
Average elevation: 13 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: rainforest
Kōkakos are a long lived species. The North Island Kōkako Recovery Plan, conducted in 1999 to 2006, states that the oldest documented kōkako in the wild was 11 years old. The expected lifespan of a juvenile, who has fledged from the nest and is recruiting for a new territory, is estimated at 10.6 years old. It is believed that a kōkako can live 20 years or more. The main focus of breeding in captivity is to be able to release kōkakos into the wild to replace the dwindling, or nonexistent, populations that once flourished. Therefore, there are no known statistics for the oldest kōkako in captivity.
Average lifespan
Status: wild: 11 years.
Average lifespan
Status: wild: 10.6 years.
Average lifespan
Status: captivity: 20 years.
Kōkakos are of medium size, measuring 38 to 50 cm in length, weighing on average 219 g. 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 with a wing span averaging only 50.2 to 52.1 cm, contributing to its limited flight capability. Directly under the beak is a cobalt blue wattle; a soft mass of tissue. There is one extinct and one extant subspecies of C. cinereus. The South Island subspecies, C. c. cinera, was recently declared extinct by the New Zealand Department of Conservation in 2007. The last documented sighting of South Island kōkakos was in 1967. The North Island subspecies, C. c. wilsoni, is classified as endangered. The distinction between the North and South island kōkakos are wattle coloring. The wattle of South Island kōkakos was bright orange, while the wattle of adult North Island kōkakos is cobalt blue. Adult wattles vary in the brightness and hue depending on the age and condition of the individual bird.
Kōkako eggs have an oval shape, and are pink-grey in color with variations of brown and purple streaks and spots. Eggs are 33 to 43.75 mm in length, 22.65 to 28.35 mm in width, and weigh (±1g) 15 to 16g. Young kōkakos 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.
Range mass: 210 to 245 g.
Average mass: 219 g.
Range length: 38 to 50 cm.
Range wingspan: 50.2 to 52.1 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike; male larger; ornamentation
Though kōkakos may be relatively well hidden and protected from avian predators, introduced mammalian species have little to no difficulty seeking out and obliterating entire clutches. Kōkakos adapted alongside diurnal avian predators that rely mainly on sight to detect prey. Introduced mammalian predators, in contrast, are nocturnal and rely heavily on sight, auditory, and olfactory cues. Nests are not only untidy in structure, but reek of feces. A nest of juveniles can be detected by the human nose more than ten meters away. A combination of the smell, sound of hatchlings begging, and the nocturnal foraging habits of these unfamiliar predators, make kōkakos' nests easy targets. Adult male and female kōkakos, when attacked by a mammalian predator will respond by deserting the nest and hiding until the threat has lifted.
Known Predators:
Anti-predator Adaptations: cryptic
Kōkakos are monogamous birds that find, attract, and defend mates through song. After a juvenile fledges from the nest it begins recruitment for a pair-bond: 1 to 2 years after for females and 2 to 4 years after for males. Pair-bonding is not restricted to male and female matches, but can include female-female and male-male. Female-female pair-bonds will form an attachment to a territory for a short period of time, and attempt to mate at least once per season. These bonds are not recorded in recent literature due to increasing predation of nesting females by introduced mammalian species. In contrast, male-male pair-bonds occur regularly. Many experts believe that this is a recent phenomenon that is a direct result of the surplus male population, but others speculate that juvenile males will choose a same sex bond even when there are females available. Mating-pairs usually stay with the same partner for many years. 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. Kōkakos sexual selection is based on female choice. Females have been known to travel to up to nine different unpaired male territories before settling on a mate. Initially, the female is drawn to a male’s territory by the phrasing of his song, but a definitive choice is made based on the quality of resources within the territory and the physicality (body size, color of plumage, 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. Kōkakos' antiphonic duets relays the identity of the pair, how long they have been bonded, and the level of dedication to neighboring territories. During the dawn chorus a pair-bond or single kōkakos will perch at the top of a tall tree, usually a podocarp, within its territory and perform the duet or single song. The tall perch allows the birds to see their neighbors and enables them to be heard.
Mating System: monogamous
Once a mating pair is established in a territory, nesting and reproduction begins. The breeding season runs on average from October to March, but for some ‘good’ seasons can extend six months after. ‘Good’ and ‘bad’ seasons seem to have a correlation with fruit availability, which makes up a large portion of kōkakos' diets. During a mating season kōkakos 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 4 to 5 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 on average before hatching, and chicks weigh 15 to 16 g at birth. During the first ten days of the chick’s life it experiences a growth rate of 10 g per day. The chicks stay in the nest for a period of 34 to more than 42 days before fledging, and even after fledging stay with their parents for 10 to 12 weeks. After a juvenile has fledged, on average, a female becomes sexually mature in 1 to 2 years, while a male becomes sexually mature within 2 to 4 years. At this time both the male and female begin recruitment for a pair-bond.
Breeding interval: Kokakos have been known to breed up to five times within one, annual breeding season.
Breeding season: The breeding season for Kokakos begins in October and runs until February.
Range eggs per season: 3 to 9.
Average time to hatching: 18 days.
Range fledging age: 31 to 42 days.
Average fledging age: 34 days.
Range time to independence: 10 to 12 weeks.
Range age at sexual or reproductive maturity (female): 1 to 2 years.
Range age at sexual or reproductive maturity (male): 2 to 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
At birth, kōkakos are altricial and are incapable of taking care of themselves. A day old chick hatches with its eyes closed, no feathers, and limited movement, relying entirely on parental care for the first month and a half of its life. For kōkakos, the parental investment of the female is much more involved than that of the male. Pre-fertilization the female builds the nest almost completely on her own. The male does present some twigs and foliage to the female for nest building, while performing an ‘archangel’ display (found in greater detail in the mating system section). Male kōkakos are not incapable of building a nest. It is common for males to build nests when they form male-male pair-bonds. The nest is a bowl shaped, untidy mass made of a twig base, and entwined moss, lichen, ferns, treefern scales, epiphytic orchid, and dead wood built 2 to 32 m above the ground. The longest recorded time for nest construction is 11 days, but usually it is only a 2 to 5 day process. When the female begins construction she randomly gathers bits and pieces, spending very little time, but as the time to lay her eggs becomes closer she focuses more on the construction.
Before hatching, females and eggs are most vulnerable to predation. Nests are generally well hidden from areal predators by the thick canopy, but are defenseless against introduced mammalian predators, such as possums. When a nest is threatened by indigenous avian predators, such as Australasain harriers and New Zealand falcons, the pair will flee the nest to hide and delay returning until it is safe to come back or desert the nest completely. In the event of a mammalian threat males will hide and delay returning, while females either hide with the male or stay on the nest to become prey along with their eggs. When a nest is threatened by cuckoos, however, kōkakos will launch a physical attack on the invading bird.
Before fledging, both the male and the female will take part in feeding young, foraging with one another. Food for the chicks is brought back to the nest in the beak and throat. Parental investment is reduced as the brood becomes more independent. The length before independence varies from nest to nest. Some parents will 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. As an example, juvenile kōkakos in the Rotoehu forest would travel on average 1,450 m in search of a suitable territory.
Parental Investment: altricial ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
The South Island kōkako (Callaeas cinereus) is a possibly extinct forest bird endemic to the South Island of New Zealand. Unlike its close relative, the North Island kōkako (C. wilsoni), it has largely orange wattles, with only a small patch of blue at the base, and was also known as the orange-wattled crow (though it was not a corvid). The last accepted sighting in 2007 was the first considered genuine since 1967, although there have been several other unauthenticated reports.[1]
The South Island kōkako was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He coined the binomial name Glaucopis cinerea.[2][3] The specific epithet cinereus is Latin meaning "ash-grey" or "ash-coloured".[4] Gmelin based his description on the "cinereous wattle-bird" that had been described and illustrated in 1781 by the English ornithologist John Latham in his book A General Synopsis of Birds. Latham had examined a specimen in the Leverian Museum in London that had come from New Zealand.[5]
The North Island kokako was formerly considered as subspecies of Callaeas cinerea, but since 2001 North Island birds have been officially recognised as C. wilsoni, and genetic evidence confirms their difference.[6] Although the genus Callaeas is masculine, the species epithet cinerea is not masculinised to match, though some authors have argued it should be.[6]
.jpg)
Like the North Island kōkako, this was a slate-grey bird with long legs and a small black mask; Reischek considered its plumage slightly lighter than the North Island species. Its wattles were distinctly orange in colour with a dark blue base; young birds had much lighter wattles.[7] It seems to have spent more time on the ground than the North Island species, but been a better flier.[8] Kōkako have distinctive organ- and flute-like duetting calls. Early explorer Charlie Douglas described the South Island kōkako call: "Their notes are very few, but the sweetest and most mellow toned I ever heard a bird produce."[9] Based on extant records, South Island kōkako eggs were larger than their North Island counterparts.[10]
At the time of European settlement, South Island kōkako were found on the West Coast from northwest Nelson to Fiordland, as well as Stewart Island, Banks Peninsula, and the Catlins. Subfossil bones suggest they were formerly found throughout the South Island, but forest burning by Polynesians eliminated them from dry eastern lowland forest.[8] Introduced mammalian predators and forest clearance by settlers reduced their numbers further: by 1900 the bird was uncommon in the South Island and Stewart Island, and had almost disappeared by 1960.[8] Its vulnerability compared to the North Island species was perhaps due to its foraging and nesting close to the ground.[11]
The South Island kōkako was formally declared extinct by the Department of Conservation in 2007, as it had been 40 years since the last authenticated sighting at Mt Aspiring in 1967.[12] In November 2013, however, the Ornithological Society of New Zealand accepted as genuine a reported sighting by two people near Reefton in 2007, and changed the bird's New Zealand Threat Classification status from "extinct" to "data deficient". Eleven other sightings from 1990 to 2008 were considered to be only "possible" or "probable".[13]
A supposed kōkako feather was found in 1995,[14] but examination by scientists at the National Museum showed it to be from a blackbird, though doubt over this conclusion exists due to the morphology of the feather and the identity of the feather used for the DNA test.[1] Unconfirmed sightings of South Island kōkako and reports of calls have continued,[15][16][17][18] but no authenticated recent remains, feathers, droppings, video, or photographs exist. The IUCN Red List status of the species is, as of 2016, Critically Endangered (Possibly Extinct).[19] The most recent unconfirmed sighting was in November 2018, in the Heaphy Track in Kahurangi National Park.[20] A potential kōkako call, consisting of a "a distinct couple of soft long notes" was recorded at Heaphy Track on 29 December 2021, followed by a sighting of "a bird of the right size and colour".[21][22]
The South Island kōkako (Callaeas cinereus) is a possibly extinct forest bird endemic to the South Island of New Zealand. Unlike its close relative, the North Island kōkako (C. wilsoni), it has largely orange wattles, with only a small patch of blue at the base, and was also known as the orange-wattled crow (though it was not a corvid). The last accepted sighting in 2007 was the first considered genuine since 1967, although there have been several other unauthenticated reports.
