This work falls into two parts. The first section gives a short general summary of the plumage of birds, its structure, arrangement and functions and briefly reviews the various types of moult patterns which are found and the ways of recording them. The second part gives a systematic species-by-species account of points including the number of flight feathers, the sequence, season and rate of moult, its relationship to breeding and migration, and the extent of the post-juvenile moult. In addition, scatter diagrams of primary moult score plotted against date are given for some species.