Blue-fronted Amazon as we see it, and then how it may be visible to another bird that has the advantage of ultraviolet receptors in its eyes.
sharing of the raising of young, nest building and mutual protection. The use of simple tools has been observed
in the wild in large macaws, Kea, Palm Cockatoo and the African grey parrot, as well as being reported regularly in companion parrot species such as Goffin’s Cockatoos and the Greater Vasa. Many video clips of ‘dancing’ parrots demonstrate that they have a genuine innate sense of rhythm. Then followed the first of some
fascinating facts and figures relating to the anatomy and physiology of intelligence. Mark told us that the total brain density of parrots is twice that of primates, whilst the grey matter (important in processing conscious information) has four times the density in parrots compared with primates. Further, humans and chickens have just 19% of their total brain neurons in the grey matter, whereas parrots have 70% of their neurons in this processing section of the brain. All this means that there is a
28 BIRD SCENE
greater density of processing power in a smaller volume, offering some four times the processing speed and reaction time in a parrot against that of a mammal. This obviously has significant influence on their ability to fly rapidly through trees and to evade predators. Mark then moved on to the special vision of parrots. Humans have three types of colour receptor cells (or cones) in their eyes, capable of detecting Red, Green and Blue wavelengths of light. Combinations of these three basic colours give us the spectrum that we see. Parrots however have four types of cone, with the fourth receiving ultra-violet wavelengths.
Blue-fronted Amazon parrots were studied under UV light, with particular reference to their wing and head feathers. These are areas of the body most used in courtship display. Sex of the birds was determined with 100% accuracy using the colour difference.
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