The Ground Parrot (Pezoporus wallicus) is one of only four ground-dwelling parrots in the world, the others being its closest relative, the extremely rare Night Parrot (Pezoporus occidentalis), the somewhat closely related Antipodes Island Parakeet (Cyanoramphus unicolor), and the unrelated highly endangered Kakapo (Strigops habroptila) from New Zealand.
The coloration of the two Pezoporus species and the Kakapo is similar – yellowish-green with darker barring, somewhat reminiscent of the head and back of the wild-type budgerigar. This is not an indication of a true relationship, however, but either adaptation to a particular lifestyle or a feature retained from ancestral parrots; probably the latter as barred plumage is found all over the family, from the tiny tiger parrots to female cockatiels.
When disturbed, the Ground Parrot flies swiftly just above the ground before dropping back into the vegetation. The presence of the bird is often only revealed by its characteristic dusk and dawn call, a clear whistling sequence of notes which rise in pitch before fading. It is silent in flight..
Check out the entire Wikipedia article, Ground Parrot, to learn more.
And, as long as we're at it, here's a short video showing the bird in its natural habitat: