Eclectus Parrots make a colourful couple - the males are a brilliant green and the females are a bright red. When specimens were first sent to Europe to be classified scientists thought they were two different species. Differences in appearance between male and female members of a species is called sexual dimorphism. In birds the plumage colour and pattern are often different. Usually males have bright colours and the female are less conspicuous. Sometimes both sexes are bright or strongly patterned, but quite different.