Ardea Official journal of the Netherlands Ornithologists' Union |
Danchin E. (1992) Food shortage as a factor in the 1988 Kittiwake Rissa tridactyla breeding failure in Shetland. ARDEA 80 (1): 93-98 |
During June-July 1988, 33 Kittiwake Rissa tridactyla colonies were studied in Shetland, Orkney, north-east England, and France. Dead and weak chicks in the nest were common in Shetland and Orkney but not in north-east England. Most Kittiwake chicks in Shetland died or disappeared when less than 20 days old. As a result, the average brood size declined to zero overtime prior to fledging. In Orkney, breeding success was less affected than in Shetland, because chicks started to die when they were almost ready to fledge. Chicks in Shetland and Orkney were leaner than those in northeast England. When handled, fewer chicks and adults in Shetland regurgitated, and chicks that regurgitated did so fewer times than in Orkney and north-east England. Fewer chicks and adults in Shetland and Orkney defecated than elsewhere. The data presented suggest that the Kittiwake breeding failure in Shetland in 1988 was primarily due to food shortage. |