THE EFFECT OF AGE AND DENSITY OF BREEDING BIRDS ON THE TIME OF BREEDING OF THE KITTIWAKE RISSA TRIDACTYLA

• Published in: Ibis
• Main Authors: Coulson, J. C., White, E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1959
• Subjects: rissa tridactyla
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1959.tb02406.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1959.tb02406.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1959.tb02406.x

Abstract In 1938, Fraser Darling put forward the concept of “social stimulation” This hypothesis postulated that colonial‐nesting birds received stimulation from their neighbours which resulted in earlier breeding, a shorter spread of the nesting period in the colony and greater breeding success. Darling's hypothesis has been criticized from a number of points of view. His original data were not sufficient to show significant differences between the behaviour of large and small colonies of the Herring Gull Larus argentatus and of the Lesser Blackbacked Gull L. fuscus. Furthermore, the present authors have shown that large colonies of the Kittiwake Rissa tridactyla have a longer nesting period than small colonies. While these and other facts cast doubt on the importance of the “Fraser Darling effect” they do not disprove the possibility that neighbouring birds in a colony may stimulate each other. Studies have therefore been undertaken on colonies of the Kittiwake on the Durham, Northumberland and East Lothian coasts to test as thoroughly as possible whether or not social stimulation is of importance to colonial‐nesting birds. The colonies studied in greatest detail were close together and it is possible to exclude the possible effects of the physical environment affecting the colonies in a different manner. Differences of up to 21 days were observed between the mean time of breeding of nine colonies, and since the differences were greatest in the youngest colonies, the effect of differences in the age composition of the colonies was considered. A study of colourringed Kittiwakes showed that females which were breeding for at least the fourth time bred 9.8 days earlier than females which were breeding for the first time. When, however, the age composition of the colonies was determined, it was always found that less than 20% of the observed differences in the time of breeding could be accounted for by differences in the age composition. A study of the nest densities within individual colonies showed that the time ...