Kakapo the "booms" (see below for a recording) and "chings" of their mating calls, they will often loudly "skraark". The kakapo has a well-developed sense of smell, which complements its nocturnal lifestyle. It can distinguish between odours while foraging, a behaviour reported in only one other parrot species. The kakapo has a large olfactory bulb ratio (longest diameter of the olfactory bulb/longest diameter of the brain) indicating that it does, indeed, have a more developed sense of smell than other parrots. One of the most striking characteristics of the kakapo is its distinct musty-sweet odour. The smell often alerts predators to
Kakapo supplementary feeding of females. Kakapo breed only once every two to five years, when certain plant species, primarily "Dacrydium cupressinum" (rimu), produce protein-rich fruit and seeds. During breeding years when rimu masts supplementary food is provided to kakapo to increase the likelihood of individuals successfully breeding. In 1989, six preferred foods (apples, sweet potatoes, almonds, Brazil nuts, sunflower seeds and walnuts) were supplied "ad libitum" each night to 12 feeding stations. Males and females ate the supplied foods, and females nested on Little Barrier Island in the summers of 1989–91 for the first time since 1982, although nesting success was