The special term for the kakapo’s ritualistic breeding habit, which includes a nightly competition among male kakapos, is lek breeding.
The male builds an elaborate series of tracks and bowls. The bowls act as the nest site, while the tracks are pathways to the nests for the females. This track-and-bowl system left nests vulnerable when predators still occupied the island native to kakapos. During breeding season, which can last two to three months, the male kakapos sit in the bowls and make a series of vocalizations in hopes of luring a female kakapo. This vocalization is what comprises the lek-breeding competition.
The vocalizations of kakapos are called booms and chings. The booms are low sounds that can travel up to 5 kilometers through the mountainous island terrain. The chings are more metallic sounds that help lead the females to the bowls.
The male kakapo continues to boom until a female approaches the bowl and successfully breeds. As many as one thousand booms have been recorded from a single male kakapo in one night. Kakapos are nothing if not persistent. Female kakapos only breed if the food supply on the island is sufficient enough to sustain the young birds. Kakapos will skip years of breeding, particularly if the rimu fruit isn’t in plentiful supply.
Once the clutch of one to four eggs hatches, the female kakapo is the primary caregiver for the chicks; all the foraging and feeding of the chicks is done by her. The feeding lasts approximately 10 weeks until the chicks fledge, but they may be fed for up to six months after that as their survival skills improve.