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 Mustelids have never colonised Stewart Island/Rakiura, but feral cats were present. During a survey, it was apparent that cats killed kakapo at a rate of 56% per year. At this rate, the birds could not survive on the island and therefore an intensive cat control was introduced in 1982, after which no cat-killed kakapo were found. However, to ensure the survival of the remaining birds, scientists decided later that this population should be transferred to predator-free islands; this operation was carried out between 1982 and 1997. In 1989, a Kakapo Recovery plan was developed, and a Kakapo Recovery programme was