Kakapo the reason for its massive decline since the introduction of dogs, cats and mustelids (see "Conservation: Human impact"). The kakapo is the only species of flightless parrot in the world, and the only flightless bird that has a lek breeding system. Males loosely gather in an arena and compete with each other to attract females. Females listen to the males as they display, or "lek". They choose a mate based on the quality of his display; they are not pursued by the males in any overt way. No pair bond is formed; males and females meet only to mate. During
Kakapo by 1976 the kakapo was gone from the valley floors and only a few males survived high on the most inaccessible parts of the cliffs. Before 1977, no expedition had been to Stewart Island/Rakiura to search for the bird. In 1977, sightings of kakapo were reported on Stewart Island. An expedition to the island found a track and bowl system on its first day; soon after, it located several dozen kakapo. The finding in an 8,000-hectare area of fire-modified scrubland and forest raised hope that the population would include females. The total population was estimated at 100 to 200 birds.