The eclectus parrots are the most sexually dimorphic of all the parrot species. The contrast between the brilliant emerald green plumage of the male and the deep red/purple plumage of the female is so marked that the birds were, until the early 20th century, considered to be different species. Eclectus parrots generally have a big head and a short tail, and are striking in their coloration. They measure about in length. Usually when birds exhibit reversed sexual dimorphism, it comes with a sex role reversal, in which the males who usually gather food are left to incubate eggs, while the female forages. It is important to note that in the eclectus, no such sex role reversal occurs. The male still forages, while the female incubates the eggs. Research has shown this dimorphism with no role reversal is a product of the rare nest hollows, and the selective pressures that accompany this. It is thought that sexual selection has affected these birds in this way in order to provide camouflage for the male, while making the female a beacon, which is not what is usually seen in sexually dimorphic birds. Good nesting sites are rare to come by, so the female's bright coloration alerts other males to females with hollows in the area, with whom they can then mate. It also serves as a signal to other females that the nesting site is occupied. The male is primarily responsible for obtaining food for the female and chicks, so his green coloration provides adequate camouflage from predators, such as
peregrine falcons, while he is in the rainforest canopy in search of food. The male also has
UV coloration in his feathers, which allows him to appear extra radiant to females, who are able to visualize the UV spectrum, yet remain camouflaged to predators who cannot. This unique coloration is evidence of an evolutionary compromise between the need to attract and compete for mates, and the risk of predation. The reported lifespan of
Eclectus sp. varies widely, from ~20 years to more than 60 years. This range is largely due to their relatively recent popularity in aviculture, with many individuals in captivity having not yet reached their natural lifespan. Many owners of eclectus parrots have reported ages upwards of 45 years, noting their birds show no obvious signs of age-related health decline. == Taxonomy ==