Cockatoo species have a mobile crest of feathers on the top of their heads, which they can raise for display, and retract. No other parrots can do so, but the Pacific lorikeets in the genera Vini and Phigys can ruffle the feathers of the crown and nape, and the red-fan parrot (or hawk-headed parrot) has a prominent feather neck frill that it can raise and lower at will.
The predominant color of plumage in parrots is green, though most species have some red or another color in small quantities. Cockatoos, however, are predominately black or white with some red, pink, or yellow. Strong sexual dimorphism in plumage is not typical among parrots, with some notable exceptions, the most striking being the eclectus parrot.:202–207 However it has been shown that some parrot species exhibit sexually dimorphic plumage in the ultraviolet spectrum, normally invisible to humans .