Kakapo "The Unnatural History of the Kakapo" won two major awards at the Reel Earth Environmental Film Festival. Two of the most significant documentaries, both made by NHNZ, are "Kakapo – Night Parrot" (1982) and "To Save the Kakapo" (1997). The BBC's Natural History Unit also featured the kakapo, including a sequence with Sir David Attenborough in "The Life of Birds". It was also one of the endangered animals Douglas Adams and Mark Carwardine set out to find for the radio series and book "Last Chance to See". An updated version of the series has been produced for BBC TV, in
Kakapo birds. Breeding occurs only in years when trees mast (fruit heavily), providing a plentiful food supply. Rimu mast occurs only every three to five years, so in rimu-dominant forests, such as those on Whenua Hou, kakapo breeding occurs as infrequently. Another aspect of the kakapo's breeding system is that a female can alter the sex ratio of her offspring depending on her condition. A female in good condition produces more male offspring (males have 30%–40% more body weight than females). Females produce offspring biased towards the dispersive sex when competition for resources (such as food) is high and towards the