What's in a name? Nomenclature for colour aberrations in birds reviewed

A review is presented of the seven commonest types colour aberrations in birds together with suggestions for a standardised universal nomenclature to identify and distinguish these aberrations. These are: Leucism (congenital absence melanin-producing cells), Progressive Greying (progressive loss Albino (total melanin due lack key enzyme), Brown (incompletely coloured melanin), Ino (even less completely Dilution (altered deposition melanin) Melanism distribution melanin). It proposed that terms should be based not only on resulting plumage but also underlying processes aberrant pigmentation. By reviewing previously used aberrations, cross-referencing my terminology, errors earlier names are pointed out, more comprehensive found wild birds. ‘There has been some confusion past recording description variant plumages … this paper represents an attempt clarify parts it.’ (Harrison 1963a)