REFERENCES
- ACOCKS , J. P. H. 1953 . Veld Types of South Africa. . Bot. Surv. S. Afr. Mem. , : 28
- BEADLE , L. C. 1962 . The evolution of species in the lakes of East Africa. . Uganda J. , 26 : 44 – 54 .
- BRODKORB , P. 1960 . How many species of birds have evolved? . Bull. Florida State Mus. Biol. Sci. , 5 ( 3 ) : 41 – 53 .
- BROOKE , R. K. 1963 . Birds round Salisbury (Rhodesia), then and now. . S. Afr. Avif. Ser. , : 9
- CAWKELL , E. M. and MOREAU , R. E. 1963 . Notes on birds in the Gambia. . Ibis. , 105 : 156 – 178 .
- GILL , E. L. 1952 . Some first records for the Cape. . Bokmakierie , 4 : 27 – 29 .
- HALL , B. P. 1963 . The francolins; a study in speciation. . Bull. Brit. Mus. (Nat. Hist.) Zool. , 10 ( 2 ) : 107 – 204 .
- JOHNSTON , R. F. and SELANDER , R. K. 1964 . House Sparrows: rapid evolution of races in North America. . Science , 144 : 548 – 550 .
- MOREAU , R. E. 1930 . On the age of some races of birds. . Ibis , 6 : 229 – 239 . (12)
- MOREAU , R. E. 1952 . The place of Africa in the Palaearctic migration system. . Anim. Eeol. , 21 : 250 – 271 .
- MOREAU , R. E. 1955 . Ecological changes in the Palaearctic region since the Pliocene. . Proc. Zool. Soc. Lond. , 125 : 253 – 295 .
- MOREAU , R. E. 1963 . Vicissitudes of the African biomes in the Late Pleistocene. . Proc. Zool. Soc. Lond. , 141 : 395 – 421 .
- ROWAN , M. K. 1963 . Range of the Cliff Swallow. . Ostrich , 34 : 181 – 182 .
- SCHÜZ , E. 1952 . Vom Vogelzug, Frankfurt/Main
- SKEAD , C. J. 1952 . The status of the Cattle Egret Ardeola ibis in the Eastern Cape Province. . Ostrich , 23 : 186 – 218 .
- SMITH , K. D. 1957 . An annotated check list of the birds of Eritrea. . Ibis , 99 : 1 – 26 .