SOCIAL STIMULATION OF REPRODUCTION IN HERRING AND LESSER BLACK‐BACKED GULLS

• Published in: Ibis
• Main Authors: MacRoberts, Barbara R., MacRoberts, Michael H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1972
• Subjects: Lesser black-backed gull
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1972.tb00851.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1972.tb00851.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1972.tb00851.x

Summary The date of the first egg laid and the position of nests were recorded for all pairs in 10 study areas within the mixed Herring and Lesser Black‐backed Gull colony on the southern end of Walney Island, Lancashire. The study areas differed from one another in density of breeding birds and in proportion of each species. These data were collected in order to determine if evidence could be found for synchrony of reproduction by social stimulation (the “Fraser Darling Effect”). The gulls in different study areas showed considerable variability in onset and spread of laying; however, attempts to correlate a number of variables, such as density of breeding birds in each area with median date or spread of laying, average nearest neighbour distance with median date of egg‐laying, and median laying date for one species with that of the other species in the same section of the gullery, failed to produce convincing evidence for inter‐ or intraspeciiic social stimulation of reproduction.