 The kakapo was a very successful species in pre @-@ human New Zealand , and one of the reasons for this was their set of adaptations to effectively avoid predation from native birds of prey , which were their only predators in the past . However , these same <unk> have been of no use to them when faced with the mammalian predators which were introduced to New Zealand after human settlement , because these hunt in different ways . As hunters , birds behave very differently from mammals , relying on their powerful vision to find prey , and thus they usually ( with the exception of owls ) hunt by day . Apart from the two surviving New Zealand raptors , the New Zealand falcon and swamp harrier , there were two other birds of prey in pre @-@ human New Zealand : <unk> 's eagle and <unk> ' harrier . All four species soared overhead searching for prey in daylight , and to avoid these avian predators , the kakapo 's ancestors adopted camouflaged plumage and became nocturnal . In addition , when the kakapo feels threatened , it freezes , so that it is more effectively camouflaged in the forest vegetation which their plumage resembles . It was not entirely safe at night , when the laughing owl was active , and it is apparent from their nest deposits on Canterbury limestone cliffs that the kakapo was among their prey . 
