Callaeas cinereuskokako

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Geographic Range

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. (Clout and Hay, 1989; Innes, et al., 1999; Rowe and Bell, 2007)

Habitat

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. ("North Island kokako recovery plan 1999 - 2009", 1999; Flux, et al., 2006; Powlesland, 1987)

  • Range elevation
    2 to 38 m
    6.56 to 124.67 ft
  • Average elevation
    13 m
    42.65 ft

Physical Description

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. (Benstead, et al., 2011; Buller, 1888; Clout and Hay, 1989; Flux and Innes, 2001; Flux, et al., 2006; "Callaeas cinereus (Kokako)", 2010; Molles and Waas, 2006)

  • Range mass
    210 to 245 g
    7.40 to 8.63 oz
  • Average mass
    219 g
    7.72 oz
  • Range length
    38 to 50 cm
    14.96 to 19.69 in
  • Range wingspan
    50.2 to 52.1 cm
    19.76 to 20.51 in

Reproduction

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. ("North Island kokako recovery plan 1999 - 2009", 1999; Flux, et al., 2006; Molles, et al., 2006; "New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account Read more: New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account - Island, Kokakos, Female, Male, North, and Food zotero://attachment/65/#ixzz1GL0Ai6SR", 2011; Powlesland, 1987; Rowe and Bell, 2007; Sinclair, et al., 2006)

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. ("North Island kokako recovery plan 1999 - 2009", 1999; Flux, et al., 2006; Innes and Hay, 1995; Leathwick, et al., 1983; Molles, 2005; Rasch, 1991; Sinclair, et al., 2006)

  • 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

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. ("North Island kokako recovery plan 1999 - 2009", 1999; Flux, et al., 2006; Leathwick, et al., 1983; MaKenzie, 1951; Molles, et al., 2006; "New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account Read more: New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account - Island, Kokakos, Female, Male, North, and Food zotero://attachment/65/#ixzz1GL0Ai6SR", 2011)

  • 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

Lifespan/Longevity

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. ("North Island kokako recovery plan 1999 - 2009", 1999; "Preliminary results and observations on north island kokako productivity and ecology at Mapara Wildlife Reserve, King Country, July 1993 - June 1994", 1995; Innes, et al., 1999)

  • Average lifespan
    Status: wild
    11 years
  • Average lifespan
    Status: wild
    10.6 years
  • Average lifespan
    Status: captivity
    20 years

Behavior

Kōkakos only socialize with neighbors to establish territory and pair-bonds during the dawn chorus. Other than song, socialization is limited to a single pair-bond within a 4 to 14 ha territorial space. Kōkakos are very territorial and generally stay within the same area year round, for many years. Activity takes place during the day and especially dawn. Kōkakos spend most of their lives feeding, nesting, and defending territories 13 ± 7.5 m above the ground within the layers of canopy, but can also be found on the forest floor. To return to the tree tops, once at ground level, kōkakos will run up the trunk of the tree directly from the bottom. This technique is called ‘squirling’. Due its limited capabilities of flight, kōkakos rely on their long slender legs for hopping from place to place, spreading its tail and wings slightly. The character of kōkakos is described with discrepancy; some compare it with a crow: shy, inquisitive, and crafty, while others insist that it is gentle, kind, and unafraid of human interaction. ("North Island kokako recovery plan 1999 - 2009", 1999; "Preliminary results and observations on north island kokako productivity and ecology at mapara wildlife reserve, King Country, July 1992 - June 1993", 1995; Buller, 1888; Flux, et al., 2006; Innes and Hay, 1995; MaKenzie, 1951; Molles and Waas, 2006)

  • Range territory size
    .04 to .12 km^2
  • Average territory size
    .14 km^2

Home Range

Kōkakos live in territories that are 4 to 14 hectares, spending most of their time in the canopy and the upper understory. The forests that they inhabit are found at the northern and central portion of the North Island of New Zealand. ("North Island kokako recovery plan 1999 - 2009", 1999; Innes, et al., 1999; Powlesland, 1987)

Communication and Perception

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. (Molles and Waas, 2006; Rowe and Bell, 2007)

Food Habits

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. (Innes and Hay, 1995; Leathwick, et al., 1983; Powlesland, 1987)

  • Animal Foods
  • insects
  • Plant Foods
  • leaves
  • fruit
  • flowers

Predation

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. ("Preliminary results and observations on north island kokako productivity and ecology at mapara wildlife reserve, King Country, July 1992 - June 1993", 1995; Flux, et al., 2006; Innes and Hay, 1995; Innes, et al., 1999)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

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. (Rasch, 1991)

Economic Importance for Humans: Positive

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. (Innes, et al., 1999; Lamb, et al., 2001)

Economic Importance for Humans: Negative

Kōkakos have no known negative effects on the economy.

Conservation Status

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. (Innes and Hay, 1995; Lamb, et al., 2001; Leathwick, et al., 1983; MaKenzie, 1951; "New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account Read more: New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account - Island, Kokakos, Female, Male, North, and Food zotero://attachment/65/#ixzz1GL0Ai6SR", 2011)

Contributors

Sarah Harrison (author), Northern Michigan University, Mary Martin (editor), Northern Michigan University, Rachelle Sterling (editor), Special Projects.

Glossary

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

diurnal
  1. active during the day, 2. lasting for one day.
duets

to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

island endemic

animals that live only on an island or set of islands.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oceanic islands

islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

rainforest

rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

visual

uses sight to communicate

References

International Union for Conservation of Nature and Natural Resources. 2010. "Callaeas cinereus (Kokako)" (On-line). The IUCN Red List of Threatened Species. Accessed March 02, 2011 at http://www.iucnredlist.org/apps/redlist/details/147126/0.

Net Industries and its Licensors. 2011. "New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account Read more: New Zealand Wattlebirds: Callaeidae - Kokako (callaeas Cinerea): Species Account - Island, Kokakos, Female, Male, North, and Food zotero://attachment/65/#ixzz1GL0Ai6SR" (On-line). NetIndustries. Accessed March 09, 2011 at http://animals.jrank.org/pages/1410/New-Zealand-Wattlebirds-Callaeidae-KOKAKO-Callaeas-cinerea-SPECIES-ACCOUNT.html.

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Department of Conservation. Preliminary results and observations on north island kokako productivity and ecology at mapara wildlife reserve, King Country, July 1992 - June 1993. 85. Wellington, New Zealand: Department of Conservation. 1995. Accessed March 10, 2011 at http://www.doc.govt.nz/upload/documents/science-and-technical/sr85.pdf.

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Molles, L., J. Waas. 2006. Are Two Heads Better Than One? Responses of the Duetting Kokako to One-and-Two Speaker Playback. Animal Behaviour, Volume 72, Iss. 1: 131-138.

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