The colours are interesting because they are the reverse of normal. In most birds the females are "self-coloured" (all one colour, and usually quite dull). Males, who compete for females, are usually brightly coloured. The essential idea is that the female should be dull or camouflaged because she carries the "precious package", the eggs. Parrots are often native to tropical forests, where green is camouflage. The males, on the other hand, need to signal their excellent health and general fitness. An extreme case would be the Twelve-wired bird-of-paradise. The implication of colouring in the "Eclectus" must be that the selection pressure is somehow different from that experienced by most bird species.