 The skeleton of the kakapo differs from other parrots in several features associated with flightlessness . Firstly , it has the smallest relative wing size of any parrot . Its wing feathers are shorter , more rounded , and less asymmetrical and have fewer distal <unk> to lock the feathers together . The sternum is small and has a low , <unk> keel and a shortened <unk> <unk> . As in other flightless birds and some other flighted parrots , the <unk> is not fused but consists of a pair of <unk> lying in contact with each coracoid . As in other flightless birds , the angle between the coracoid and sternum is enlarged . The kakapo has a larger <unk> than other parrots . The <unk> bones of the leg and arm are disproportionately long and the distal elements are disproportionately short . 
