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 and weka kept appearing. 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. Along with Mana Island, it was replaced with two new kakapo sanctuaries: Chalky Island (Te Kakahu) and Anchor Island. The entire kakapo population of Codfish Island was temporarily relocated in 1999 to Pearl Island in Port Pegasus while rats were being eliminated from Codfish. All kakapo on Pearl and Chalky Islands were moved to Anchor Island in 2005. A key part of the Recovery Programme is the