Kakapo  (Strigops habroptilus)

The kakapo is a Critically Endangered, giant, nocturnal parrot. It is a classic example of evolution on an isolated island; and has a number of characteristic features that make this species unique. It is the only member of the subfamily Strigopinae and is the only flightless parrot in the world. It is also the largest parrot known and is possibly the longest-lived; the oldest known bird was elderly when found in 1975 and was still alive in 2002 (3). Adults have beautiful mossy green plumage mottled with brown and yellow, which provides excellent camouflage against the forest floor (5). The face is owl-like (5), yellowish-brown (6), and framed with modified whisker-like feathers (2). Juveniles are slightly duller in colour than adults and have browner faces (6). The feathers are downy and soft; the scientific name habroptilus means soft feathers (6).

This subfamily is endemic to New Zealand, and was once widespread within the North, South and Stewart Islands, but is now extinct throughout this former range (2). Between 1980 and 1997 (3), all kakapo remaining on Stewart Island were transported to offshore, predator-free islands in order to protect them from introduced mammalian carnivores. The species now occurs on Codfish and Chalky Islands (3).

Formerly inhabited a wide range of habitat types, including lowland Podocarp forests, upland beech (Nothofagus) forests and subalpine scrublands (3).

The kakapo is the only parrot to have a lek mating system (5); early in the breeding season (between December and April) (3), males gather on display grounds where a number of bowl shaped depressions are dug out in the ground. Having competed for access to the best locations, a male settles into a bowl and then begins to 'boom' to attract females (5). This strange, very low frequency call can be heard up to five kilomentres away, and obtains its resonance via inflatable throat air sacs; lek-displaying males also make a metallic, high pitched 'ching' call (5). After mating, females incubate the eggs and rear the chicks alone. Two to three eggs are usually produced and the chicks hatch after 30 days (5). Sexual maturity is not reached until nine to ten years of age; furthermore, breeding is erratic and slow, occurring every two to five years and is dictated by the infrequent availability of super-abundant food supplies (3). One such event is the 'mast fruiting' of the 'rimu' tree (Dacrydium cupressinum), which only occurs every two to five years (7). The kakapo feeds on a variety of fruits, seeds, roots, stems, leaves, nectar and fungi (5). Today, introduced plants are important foods on some islands (3).

The first human settlers of New Zealand were the Maori, who hunted kakapo for their feathers and meat; the Polynesian dog and rat introduced by the Maori also preyed upon the species (5). When Europeans began to settle in the 1800s the range of the kakapo had already dramatically declined, and the situation became critical as Europeans set about clearing forests, hunting and releasing mammalian predators such as domestic cats, dogs, stoats and rats. The kakapo is particularly vulnerable to predation by mammals due to its strong scent, habit of freezing when threatened, and especially its ground nesting behaviour (5), and flightlessness; the latter, together with very slow breeding strategies are key elements in the demise of many endangered and extinct New Zealand species (8). Introduced possums and deer compete with the kakapo for food sources (5).

The drastic measure of removing all surviving kakapo to predator-free islands has averted extinction of this remarkable bird. There is a National Kakapo Team and a ten-year Recovery Plan for the species (5). Measures to conserve the kakapo include intensive, invasive management of free-living individuals, including supplementary feeding in order to stimulate and support breeding, and measures to improve the survival of chicks. Although research and management are ongoing the dedication and hard work have paid off and initial results are very encouraging; the population has increased from 51 individuals in 1995 to 86 in 2002 (3). Unfortunately, in July 2004 three young female kakapo died as the result of a mystery infection, taking the total population down to 83 individuals. New Zealand's Department of Conservation was quick to respond, giving the remaining birds antibiotics (9).

For more information on the kakapo see:

• Kakapo Recovery Programme:
  www.kakapo.org.nz/
• BirdLife International (2000) Threatened Birds of the World. Lynx Edicions and BirdLife International, Barcelona and Cambridge.
• Merton, D.V. (1999) Kakapo. In: Higgins P.J. (Ed.) Handbook of Australian, New Zealand & Antarctic Birds. Vol. 4. RAOU. Oxford University Press, Melbourne.
• BirdLife International's World Bird Database:
  www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=1492&m=0

Authenticated by Don Merton (23/9/02), Kakapo Management Group, New Zealand Department of Conservation.
http://www.kakapo.org.nz/