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 of the kakapo until George Gray of the British Museum described it from a skin in 1845. As the Māori had done, early European explorers and their dogs ate kakapo. In the late 19th century, the kakapo became well known as a scientific curiosity, and thousands were captured or killed for zoos, museums and collectors. Most captured specimens died within months. From at least the 1870s, collectors knew the kakapo population was declining; their prime concern was to collect as many as possible before the bird became extinct. In the 1880s, large numbers of mustelids (stoats, ferrets and weasels) were