Kōkako
| Kōkako | |
|---|---|
 | |
| Conservation status | |
 Endangered (IUCN 3.1) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Callaeidae |
| Genus: | Callaeas J.R. Forster, 1788 |
| Species: | C. cinereus C. cinerea cinerea |
| Binomial name | |
| Callaeas cinereus (Gmelin, 1788) | |
| Synonyms | |
Callaeas cinerea
| |
The Kōkako (Callaeas cinereus) is a forest bird which is endemic to New Zealand. It is slate-grey with wattles and a black mask. It is one of three species of New Zealand Wattlebird, the other two being the endangered Tieke (saddleback) and the extinct Huia. Previously widespread, Kōkako populations throughout New Zealand have been decimated by the predations of mammalian invasive species such as possums, stoats, cats and rats and their range has contracted significantly. There were formerly two sub-species of Kōkako, North Island and South Island, although the South Island subspecies may now be extinct. In the past this bird was called the New Zealand Crow: it is not a crow at all, but it looks like one from a distance.
Taxonomy
The Kōkako was first described by German naturalist Johann Friedrich Gmelin in 1788. Its species name is the Latin adjective cinereus"grey". Two subspecies have been described. The nominate subspecies from the South Island is likely to have become extinct.
The Kōkako appears to be a remnant of an early expansion of passerines in New Zealand and is one of three New Zealand wattlebirds of the family Callaeidae, the others being the endangered Tieke, or Saddleback, and the extinct Huia. New Zealand Wattlebirds have no close relatives apart from the Stitchbird, and their taxonomic relationships to other birds remain to be determined.
Description
The North Island Kōkako, Callaeas cinerea wilsoni has blue wattles (although this colour develops with age: in the young of this bird they are actually coloured a light pink).The South Island Kōkako, Callaeas cinerea cinerea, by contrast has largely orange wattles, with only a small patch of blue at the base .
Behaviour
The Kōkako has a beautiful, clear, organ-like song. Its call can carry for kilometres. Breeding pairs sing together in a bell-like duet for up to an hour in the early morning. Different populations in different parts of the North Island (if any populations of the South Island Kōkako remain they are at present unknown) have distinctly different songs which many people consider analogous with human "dialects" of a given language.
The Kōkako is a poor flier and seldom flies more than 100 metres. The wings of this species are relatively short and rounded. It prefers to hop and leap from branch to branch on its powerful grey legs. It does not fly so much as glide and when seen exhibiting this behaviour they will generally scramble up tall trees (frequently New Zealand podocarps such as rimu and matai) before gliding to others nearby. Its ecological niche is frequently compared to that of a flying squirrel. Its diet consists of leaves, fern fronds, flowers, fruit and invertebrates.
Kōkako and humans
In Māori and modern New Zealand culture
Māori myth refers to Kōkako in several stories. In one notable story, Kōkako gave Māui water as he fought the sun by filling its plump wattles with water and offering it to Māui to quench his thirst. Māui rewarded Kōkako for its kindness by stretching its legs until they were lean, long and strong, so that Kōkako could easily leap through the forest to find food.
The Kōkako appears on the reverse side of the New Zealand $50 note.
Threats and conservation
North Island kōkako
In the early 1900s the North Island Kōkako was common in forests throughout the North Island and its offshore islands. Primary causes of Kōkako decline were forest clearance by settlers and the introduction of predators such as rats, stoats and possums. The North Island Kōkako is now endangered, with an estimated 750 pairs in existence (January 2009).
Unlike many of New Zealand's most vulnerable birds, Kōkako survive in low numbers in several North Island native forests. However, research has shown that female Kōkako are particularly at risk of predation as they carry out all incubation and brooding throughout a prolonged (50-day) nesting period. Years of such predation have resulted in populations that are predominantly male and with consequent low productivity rates.
Government-funded pest control programmes, and captive breeding programmes are critical to helping maintain population numbers on the mainland. A "research by management" approach has demonstrated that the Kōkako decline can be reversed and populations maintained in mainland forests by innovative management of their habitat. Current research aims to increase management efficiency to ensure long-term Kōkako survival. The use of biodegradable 1080 poison has been particularly beneficial in reversing population decline. For example, between 1991 and 1999 the breeding population of Kōkako increased tenfold in Mapara Wildlife Reserve (Waikato) thanks to a series of four aerial 1080 operations.
New populations are also being established through releases on predator-free offshore islands. As a result, conservationists are hopeful of the species' long-term survival.
South Island Kōkako
In the early 1900s the South Island Kōkako was widespread in the South Island and Stewart Island. It has fared worse than the North Island subspecies and was formally declared extinct by the New Zealand Department of Conservation on 16 January 2007. A confirmed sighting has not occurred in several decades, though unconfirmed sightings are very occasionally reported. In the 1990s, Timberlands, the state owned enterprise tasked with managing the former New Zealand Forest Service's West Coast forests found some evidence of Kokako in the research into native forest ecology it conducted as part of its sustainable management program.
Distribution
As at 2010, North Island Kōkako were present in Pureora Forest Park,Whirinaki Forest Park,Mapara Wildlife Reserve, the Hunua Ranges,Ngapukeriki,Kaharoa Forest, the Te Urewera National Park,Puketi Forest, and the Waitakere Ranges.Kōkako can be seen relatively easily on a number of publicly accessible offshore island sanctuaries, including Tiritiri Matangi and Kapiti Island where the regenerating forest is low enough to provide close views. Captive birds can be seen at Mount Bruce Wildlife Centre and Otorohanga Kiwi House.
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