Abstract
Summary.: From experience from southern Abyssinia southwards to the Union of South Africa, 176 instances are given of no geographical voice‐variation within a single species, or pairs of allopatric species (List 1 A), as compared to only 33 instances of variation (2 A), most of which are of but small degree, and one of which is in fact ecological. In closely allied sympatric species, in some cases there is a voice‐difference (2 C), but which may be very slight. Where there is no difference at all (1 B), in some cases there is an ecological difference, but in others no such barrier exists. Variation in allopatric species of Tauraco is recorded in 2 B.A postscript gives the results of some later experience on the coasts of Angola and the Cape Province.