With few predators and abundant food, kākāpō exhibit island syndrome development, having a generally-robust torso physique at the expense of flight abilities, resulting in reduced shoulder- and wing-muscles, along with a diminished keel on the sternum.
[10][11] The generic name Strigops is derived from the Ancient Greek strix, genitive strigos ("owl"), and ops ("face"), while its specific epithet habroptilus comes from habros ("soft"), and ptilon ("feather").
[28] The kākāpō cannot fly, having relatively short wings for its size and lacking the keel on the sternum (breastbone), where the flight muscles of other birds attach.
[5] The upper parts of the kākāpō have yellowish moss-green feathers barred or mottled with black or dark brownish grey, blending well with native vegetation.
Because the feathers do not need the strength and stiffness required for flight, they are exceptionally soft, giving rise to the specific epithet habroptila.
The beak is surrounded by delicate feathers which resemble vibrissae or "whiskers"; it is possible kākāpō use these to sense the ground as they walk with its head lowered, but there is no evidence for this.
In Fiordland, areas of avalanche and slip debris with regenerating and heavily fruiting vegetation – such as five finger, wineberry, bush lawyer, tutu, hebes, and coprosmas – became known as "kākāpō gardens".
Kākāpō seem to have preferred broadleaf or mountain beech and Hall's tōtara forest with mild winters and high rainfall, but the species was not exclusively forest-dwelling.
[51][49] The kākāpō's adaptations to avoid avian predation have thus been useless against its new enemies, and the reason for its massive decline since the introduction of dogs, cats and mustelids (see Conservation: Human impact).
[55] Each court consists of one or more saucer-shaped depressions or "bowls" dug in the ground by the male, up to 10 centimetres (4 in) deep and long enough to fit the half-metre length of the bird.
[74] Due to its inability to fly, strong scent and habit of freezing when threatened, the kākāpō was easy prey for the Māori and their dogs.
A keen naturalist, Henry was aware that native birds were declining, and began catching and moving kākāpō and kiwi from the mainland to the predator-free Resolution Island.
[citation needed] In the 1950s, the New Zealand Wildlife Service was established and began making regular expeditions to search for the kākāpō, mostly in Fiordland and what is now the Kahurangi National Park in the northwest of the South Island.
[86] In the 1980s the kākāpō were translocated to islands with no predators to maintain their genetic diversity, to avoid spreading harmful diseases, and to reduce interbreeding.
None of the New Zealand islands were ideal to establish kākāpō without rehabilitation by extensive re-vegetation and the eradication of introduced mammalian predators and competitors.
Little Barrier Island was eventually viewed as unsuitable due to the rugged landscape, the thick forest and the continued presence of rats, and its birds were evacuated in 1998.
[91] In 1989, six preferred foods (apples, sweet potatoes, almonds, Brazil nuts, sunflower seeds and walnuts) were supplied ad libitum each night to 12 feeding stations.
[92] Supplementary feeding affects the sex ratio of kākāpō offspring, and can be used to increase the number of female chicks by deliberately manipulating maternal condition.
[citation needed] Today commercial parrot food is supplied to all individuals of breeding age on Whenua Hou and Anchor.
[citation needed] All kākāpō islands are now rat-free, but infrared cameras still allow rangers to remotely monitor the behaviour of females and chicks in nests.
Data loggers record when mother kākāpō come and go, allowing rangers to pick a time to check on the health of chicks, and also indicate how hard females are having to work to find food.
[96] To help meet this conservation challenge, Resolution Island (20,860 ha (51,500 acres)) in Fiordland has been prepared for kākāpō re-introduction with ecological restoration including the eradication of stoats.
[98] Four males were re-introduced to Sanctuary Mountain Maungatautari in the North Island on 21 July 2023, becoming the first kākāpō living in mainland New Zealand in almost 40 years.
[100] In 2019 an outbreak of the fungal disease aspergillosis among kākāpō on the island of Whenua Hou infected 21 individuals and led to 9 deaths: two adults, five chicks and two juveniles.
[74] One source states that its flesh "resembles lamb in taste and texture",[115] although European settlers have described the bird as having a "strong and slightly stringent [sic] flavour".
This was corroborated by European settlers in New Zealand in the 19th century, among them George Edward Grey, who once wrote in a letter to an associate that his pet kākāpō's behaviour towards him and his friends was "more like that of a dog than a bird".
Many books and documentaries detailing the plight of the kākāpō have been produced in recent years, one of the earliest being Two in the Bush, made by Gerald Durrell for the BBC in 1962.
The BBC's Natural History Unit featured the kākāpō, including a sequence with Sir David Attenborough in The Life of Birds.
An updated version of the series has been produced for BBC TV, in which Stephen Fry and Carwardine revisit the animals to see how they are getting on almost 20 years later, and in January 2009, they spent time filming the kākāpō on Codfish Island / Whenua Hou.
A study found that playing the game helped increase positive attitudes and actions related to kākāpō protection, such as support for managing invasive predators and responsible pet care, though it did not lead to more donations.