ABSTRACT
T HE DISTRIBUTION of birds in Africa south of the Sahara is now com-paratively well documented, both specifically and subspecifical1y.l Also, the taxonomy is more advanced than is true with other animals or plants. There is no doubt that with few exceptions most of the bird species are associated very closely with individual vegetation types, but detailed study of this relationship awaits more complete data. Meanwhile, there are undoubtedly certain features in the distribution of birds which are so difficult to explain in terms of the present climatic picture that it is necessary to postulate past changes on a considerable scale. This is the subject of the present study. Attention will be concentrated on groups rather than individual species, which are more liable to be misleading. Some ancillary evidence will be adduced from other groups of animals and from plants.
