This species declined very rapidly over the past three generations until the end of the 20th century, thus it qualifies as Endangered. It now has a very small effective population size because intense predation has left many subpopulations with an excess of unpaired males; however, intensive conservation efforts since 1990 that aimed to restore the population to c.1,000 pairs by the year 2020 have resulted in population increases that are more rapid than expected, so this target is set to be raised.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.
Gender agreement of species name follows David and Gosselin (2002b).
Callaeas cinerea Sibley and Monroe (1990, 1993), Callaeas cinerea Turbott (1990), Callaeas cinerea Collar and Andrew (1988), Callaeas cinerea Collar et al. (1994), Callaeas cinerea BirdLife International (2000), Callaeas cinerea BirdLife International (2004), Callaeas cinerea
Distribution and population
38 cm. Large, blue-grey bird with black mask. Black, short, thick bill. Long, thin legs. Small, round wings. North Island adult, blue wattles. South Island adult, orange wattles. Juvenile, small pink wattles. Voice Unmistakable low, slow song sounding like an organ.
This species is endemic to New Zealand
. The last confirmed sightings of the South Island subspecies cinereus
were in 1967 (Clout and Hay 1981); it is now considered extinct, with recent reports not deemed to be credible (Bain 2009). The North Island subspecies wilsoni
was formerly common throughout the island's forests, but now only survives in the Hunua Ranges, Mataraua, Kaharoa, Rotoehu, Pureora and Mapara forests, and Te Urewera National Park (Rasch 1991, Moore and Innes 1996). In June 2008, 747 pairs were recorded, giving a total population estimate of 1,650 individuals (Anon. 2008). Populations are increasing in areas of intensive conservation work including the establishment of translocated populations at Secretary Island and Omaio/East Cape (J. Innes in litt
. 2009), but continue to decline elsewhere, with those at most unmanaged sites now extinct. Observed rates of decline have been as high as 50% in three years in some areas (I. A. Flux in litt.
1999, Innes et al.
1999). Subpopulations are entirely isolated by fragmentation (I. A. Flux in litt.
1999). This species is entirely conservation-dependent, each population requiring on-going annual pest-management until at least 25 breeding pairs are present, followed by at least three years of management every 10 years to maintain population growth. Although the population is now increasing thanks to the intensive management conducted for the species, the number of locations where it is found continues to decline as unmanaged populations disappear, and over the past three generations the global population has certainly shown a very rapid decline. Population justification
In 2008 the global population contained 769 breeding pairs (J. Innes in litt.
2009). The number of mature individuals is higher, but the population has a surplus of adult males, thus the effective population size is lower. It is estimated here to number at least 1,000 mature individuals, equivalent to 1,500 individuals in total.Trend justification
Populations are increasing in areas of intensive conservation work, and these increases now predominate as populations at unmanaged sites are now extinct or functionally extinct. However, declines in the earlier part of the last three generations trend period were very rapid and hence a decline is retained at present.Ecology
The species prefers lowland, tall podocarp/hardwood forests with a high diversity of plant species. It is rarely found in modified forests, including selectively logged forests (Heather and Robertson 1997). Its diet varies seasonally. It prefers fruit, but also eats leaves, invertebrates, buds, flowers and nectar (Powlesland 1987). Shrub hardwoods are a particularly important food source (Rasch 1991). It breeds mainly from October to March, usually laying three eggs (Heather and Robertson 1997, Bain 2008). In years of high food availability, pairs will raise several clutches. The average age of parents at Mapara is 6.3 years, but this may be an underestimate of the global average as the population is young owing to intensive management (I. A. Flux in litt.
The historical decline was due to large-scale habitat destruction, fragmentation and the introduction of predators and competitors. Predation of eggs and chicks by black rats Rattus rattus
and brush-tailed possums Trichosurus vulpecula
is the main cause of nest failure, whereas deaths to nesting adult females were caused by stoats Mustela erminea
(Flux et al.
2006). These introduced predators are currently the primary threat to the species. At Mapara Wildlife Management Reserve, just 8% of nesting attempts successfully fledged young in the absence of predator control, versus 61% when predators were intensively trapped (Flux et al
. 2006). T. vulpecula
also competes for many preferred food items, and introduced goats and deer destroy favoured understorey food-plants (Innes et al.
1999). Historical forest destruction for logging has also been important, especially as the species is thought to require fairly large tracts of forest. These two threats were largely contemporaneous and so their relative importance is not completely clear (Rasch 1991).Conservation Actions Underway
Most of the remaining habitat is protected and almost all key subpopulations are managed for the control of R. rattus
and T. vulpecula
. Recent research shows that "pulsing" poison bait delivery (at least three managed years every 10) is likely to be the most effective way of dealing with the predator threat once managed populations have reached a certain size (Bassé et al.
2003). Birds have been introduced to four islands (Heather and Robertson 1997). Young females have also been introduced to two managed remnant male/predominantly male populations on the mainland (I. A. Flux in litt.
1999), and several new populations (in areas of their previous range) have been established through translocation of adults to sites at which predators are controlled. Two small captive populations are held (Heather and Robertson 1997). Populations are encouraged to stay in protected areas using playback of their calls, attracting individuals to key areas (Anon. 2008). Genetic research has been undertaken to ensure sufficient genetic diversity in each subpopulation (Bain 2008).Conservation Actions Proposed
Improve the understanding of the Te Urewera population, and modify management developed in smaller forest blocks, to assist large-scale protection and enhancement. Develop sustainable long-term management practices by research and mathematical modeling, and implement them. Support and develop captive breeding programmes, and aim to reintroduce birds to newly-managed forest areas (I. A. Flux in litt.
Anon. 2008. Kokako numbers booming. Forest and Bird: 7.
Bain, H. 2008. Keeping the Kokako's song alive. Forest and Bird: 24-26.
Bain, H. 2009. The search for the living dead? Forest and Bird: 27-29.
Basse, B., Flux, I. and Innes, J. 2003. Recovery and maintenance of the North Island kokako (Callaeas cinerea wilsoni) populations through pulsed pest control. Biological Conservation 50: 143-198.
Clout, M. N.; Hay, J. R. 1981. South Island Kokako Callaeas cinerea cinerea in Nothofagus forest. Notornis 28: 256-259.
Collar, N. J.; Butchart, S. H. M. 2013. Conservation breeding and avian diversity: chances and challenges. International Zoo Yearbook.
Flux, I.; Bradfield, P.; Innes, J. 2006. Breeding biology of North Island Kokako (Callaeas cinerea wilsoni) at Mapara Wildlife Management Reserve, King Country, New Zealand. Notornis 53(2): 199-207.
Graham, M. 2008. Kokako Recovery Group: a report on the 2008 annual meeting in Rotorua. Southern Bird: 10-11.
Heather, B. D.; Robertson, H. A. 1997. The field guide to the birds of New Zealand. Oxford University Press, Oxford, UK.
Innes, J.; Hay, R.; Flux, I.; Bradfield, P.; Speed, H.; Jansen, P. 1999. Successful recovery of North Island Kokako Callaeas cinerea wilsoni populations by adaptive management. Biological Conservation 87: 201-214.
Moore, S.; Innes, J. 1996. North Island Kokako: the cutting edge. Forest and Bird 282: 12-20.
Powlesland, R. G. 1987. The foods, foraging behaviour and habitat use of North Island Kokako in Puketi State Forest, Northland. New Zealand Journal of Ecology 10: 117-128.
Rasch, G. 1991. Recovery plan for North Island Kokako. Department of Conservation, Wellington.
Further web sources of information
New Zealand Govt - Dept of Conservation - Recovery Plan
Text account compilers
Benstead, P., Bird, J., Calvert, R., Khwaja, N., McClellan, R., Taylor, J., Temple, H.
Flux, I., Innes, J.
BirdLife International (2013) Species factsheet: Callaeas cinereus. Downloaded from
http://www.birdlife.org on 22/12/2013.
Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 22/12/2013.
This information is based upon, and updates, the information published in BirdLife International (2000)
Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004)
Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
To provide new information to update this factsheet or to correct any errors, please email BirdLife
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Additional resources for this species