FEATHER
THE earliest published record I could find referring to the loss of pigment over time in birds was from 1853, by an Austrian biologist called Frauenfeld. He divided the different colour aberrations found in birds into several groups, and one of them was “discolouring with age”. (Frauenfeld called it Geraiochromatism from the Greek or for “old age”, and “chromatism” for “colour”.) Although Frauenfeld (1853) had already noticed that normally coloured birds can lose the pigment in their plumage later in life, this phenomenon remained undocumented for another century, as it was unappreciated by many later workers.
