Great green macaws are the largest parrots in their natural range, the second heaviest macaw species (although they are relatively shorter tailed than other large macaws such as the red-and-green macaw and are thus somewhat shorter), and the third heaviest parrot species in the world. This species averages in length and in weight. They are mainly green and have a reddish forehead and pale blue lower back, rump and upper tail feathers. The tail is brownish-red tipped with very pale blue. The bare facial skin is patterned with lines of small dark feathers, which are reddish in older and female parrots. Juveniles have grey-coloured eyes instead of black, are duller in colour and have shorter tails which are tipped in yellow.