Parrots however can not only change the shape of their lens, but also have muscles that influence the cornea, meaning that they can focus on something as close as just ½” from the eye, right up to infinity.


Going back to the evolution of birds from dinosaurs, Mark stated that the first feathers were found as modified scales in a 400 lbs ostrich-like creature, and that these primitive feathers appeared only in the adult creature. This suggests that feathers were first used for display and courtship purposes, rather than for flight.


30 BIRD SCENE


Every feather on a bird’s body may be individually moved and controlled voluntarily by muscle contractions. Dr Stafford then moved on to the


methods of colour production in birds’ plumage. Melanin is a pigment providing black colour, but blue colour is demonstrated simply by the refraction of white light through the hollow structure of feathers. There is no pigment involved here. Equally, white is shown by complete reflection of light when no melanin or other pigments are present. Most birds produce yellow and red pigments from


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