Changes

These structural features of the feather can be inherent in the development of the feather.  They can also be induced by materials that are placed on the feathers after development, that alter the absorption or reflection of light.

These structural features of the feather can be inherent in the development of the feather.  They can also be induced by materials that are placed on the feathers after development, that alter the absorption or reflection of light.

If a feather reflects all light, it appears white; if it absorbs all wavelengths, it appears black.  The capacity of the barbs and barbules to scatter and reflect varying wavelengths of light causes and irridescent glow of the feathers.  Blue colours are created by the barbs interacting to reflect blue light, while allowing other wavelenghts of light to be absorbed by darker melanin granules.  Green colours may be created by pigments, or more commonly, through a combination of blue and yellow pigments.

If a feather reflects all light, it appears white; if it absorbs all wavelengths, it appears black.  The capacity of the barbs and barbules to scatter and reflect varying wavelengths of light causes an irridescent glow of the feathers.  Blue colours are created by the barbs interacting to reflect blue light, while allowing other wavelenghts of light to be absorbed by darker melanin granules.  Green colours may be created by pigments, or more commonly, through a combination of blue and yellow pigments.

===Colour mutations===

===Colour mutations===