Kakapo

The Kakapo also known as Owl Parrot (Strigops habroptilus), is a species of large flightless nocturnal parrots of the super-family Strigopoidea, endemic to New Zealand. 
These flightless birds have yellow-green plumage, a distinct facial disc, owl-style forward-facing eyes with surrounding discs of specially-textured feathers, a large grey beak, short legs, large blue feet, and relatively short wings and tail. It is the world's only flightless parrot, the world's heaviest parrot, and also is nocturnal.
Description
The kakapo cannot fly, It uses its wings for balance and to break its fall when leaping from trees.
The upper parts of the kakapo have yellowish moss-green feathers barred or mottled with black or dark brownish grey, blending well with native vegetation. Individuals may have strongly varying degrees of mottling and colour tone and intensity – museum specimens show that some birds had completely yellow colouring. The breast and flank are yellowish-green streaked with yellow. The belly, undertail, neck, and face are predominantly yellowish streaked with pale green and weakly mottled with brownish-grey.
Like many other parrots, kakapo have a variety of calls. As well as the booms and chings of their mating calls, they will often loudly skraark.
Behaviour
The kakapo is nocturnal; it roosts in trees or on the ground during the day and moves around its territories at night.
The kakapo was a very successful species in pre-human New Zealand, and was well adapted to avoid the birds of prey which were their only predators. As well as the New Zealand falcon, there were two other birds of prey in pre-human New Zealand: Haast's eagle and Eyles' harrier. All these raptors soared overhead searching for prey in daylight, and to avoid them the kakapo evolved camouflaged plumage and became nocturnal.