During the courting season, males leave their home ranges for hilltops and ridges where they establish their own mating courts. These leks can be up to from a kakapo's usual territory and are an average of apart within the lek arena. Males remain in the region of their court throughout the courting season. At the start of the breeding season, males will fight to try to secure the best courts. They confront each other with raised feathers, spread wings, open beaks, raised claws and loud screeching and growling. Fighting may leave birds with injuries or even kill them. Mating occurs only approximately every five years, with the ripening of the rimu fruit. In mating years, males making "booming" calls for 6–8 hours every night for more than four months.