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
Cuban flightless crane Cuban flightless crane The Cuban flightless crane ("Grus cubensis") is a large, extinct species of crane that was endemic to the island of Cuba in the Caribbean. The remains were found in Pleistocene deposits in Pinar del Rio. Probably derived from an early invasion of sandhill cranes from North America, it differed from that species by, as well as larger size, having a proportionately broader bill, stockier legs, and with reduced wings and pectoral girdle indicating that it may have been flightless. Currently, the only extant Caribbean crane is the Cuban sandhill crane, "Antigone canadensis nesiotes", an endangered subspecies of