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 meat as a food source and for its feathers, which were used to make highly valued pieces of clothing. Kakapo were also occasionally kept as pets. The kakapo is critically endangered; as of August 2018, the total known adult population was living individuals, all of which are named. Because of the introduction of predators such as cats, rats, ferrets, and stoats during European colonisation, the kakapo was almost wiped out. Conservation efforts began in the 1890s, but they were not very successful until the implementation of the Kakapo Recovery Programme in 1995. Most kakapo are kept on two predator-free islands,