REFERENCES
- Allen , A. A. 1930 . The Book of Bird Life
- Barth , E. K. 1955 . Egg-laying, incubation and hatching of the Common Gull . Lams canus. Ibis. , 97 ( 2 ) : 222 – 239 .
- Decker , G. 1955 . Beiträge zur Kenntnis der Nestbau-Technik Deutscher Sylviden. . J. F. Ornithol. , 96 ( 2 )
- Farkas , T. 1955 . Zur Brutbiologie und Ethologie des Steinrotels Montico-la saxatilis. . Die Vogel-welt. , 76 ( 5 ) : 170
- Gill , E. L. 1936 . A First Guide to the South African Birds
- Grassé , P. O. 1950 . Traité de Zoologie Anatomie Systematique Biologie. . Oiseaux. , : 15
- Gurr , L. 1954 . A study of the Blackbird Turdus merula in New Zealand. . Ibis. , 96 ( 2 ) : 225 – 261 .
- Herrick , F. H. 1911 . Nests and Nest-building in Birds. . Animal Behaviour. , 1 ( 2 )
- Hewitt , J. 1931 . A Guide to the Vertebrate Fauna of the Eastern Cape Province Part I Mammals and Birds
- Kendeigh , S. C. 1952 . Parental Care and its Evolution in Birds. . Illinois Biol. Monogr. , 22 ( 1–3 )
- Kluijver , H. N. 1950 . Daily Routines of the Great Tit . Parus m. major L. Ardea. , 38 : 99 – 136 .
- Lack , D. and Silva , E. T. 1949 . The Weight of Nestling Robins. . Ibis. , 91 : 64 – 78 .
- Layard , E. L. 1867 . The Birds of South Africa 74
- Lees , J. 1949 . Weight of Robins. Part I: Nestlings. . Ibis. , 91 : 79 – 88 .
- Mayaud , N. 1950 . Longévité Grassé . Traité de Zoologie. , 15 : 536 – 538 .
- Moynehan , M. 1955 . Types of Hostile Display. . Auk. , 72 : 248
- Nice , M. M. 1943 . Studies in the Life History of the Songsparrow. II. . Trans. Linn. Soc. America. , 6 ( 1–8 ) : 1 – 328 .
- Petersen , A. J. 1955 . The Breeding Cycle of the Bank Swallow. . Wilson Bulletin. , 67 ( 4 ) : 241
- Pettingill , O. S. 1956 . A Laboratory Field Manual of Ornithology
- Richdale , L. E. 1943 . The Kuaka or Diving Petrel Pelecanoides urinatrix (Gmelin). . Emu. , 43 : 24 – 48 . 97–107
- Roberts , A. 1940 . The Birds of South Africa
- Rowan , M. K. 1955 . The Breeding Biology and Behaviour of the Redwinged Starling . Onychognathus morio. Ibis. , 97 ( 4 ) : 663 – 705 .
- Rowan , M. K. 1953 . Pursuing the Robin. . Bokmakierie. , 5 ( 3 ) : 55
- Salomonsen , F. 1933 . Zur Systematik und Biologie von Promerops. . Orn. Monats b. , 41 : 37 – 40 .
- Simmons , K. E. L. 1954 . The Behaviour and General Biology of the Graceful Warbler . Prinia gracilis. Ibis. , 96 ( 2 )
- Skutch , A. F. 1952 . Hour of Laying and Hatching of Birds' Eggs. . Ibis. , 94 ( 1 )
- Skutch , A. F. 1953 . How the Male Bird discovers the Nestlings. . Ibis. , 95 ( 1 ) and (3)
- Stark , A. C. and Sclater , W. L. 1900 . The Birds of South Africa 1
- Stresemann , E. 1934 . Handbuch der Zoologie . Kükenthal. , 7 ( 2 )
- Tinbergen , N. 1951 . The Study of Instinct
- Vincent , J. 1952 . A Check List of the Birds of South Africa
- Weidmann , U. 1956 . Observations and Experiments on Egg-laying in the Blackheaded Gull . Larus ridibundus. Brit. J. Animal Behav. , 4 ( 4 ) : 150 – 161 .
- Wing , L. 1956 . Natural History of Birds A Guide to Ornithology. Check List of Birds of the S.W. Cape. 1955