Breeding success, diet, and brood neglect in the kittiwake (Rissa tridactyla) over an 11-year period

Abstract

Seabirds are frequently used as indicators of the state of the marine environment. The kittiwake (Rissa tridactyla) is a common and widespread surface-feeding seabird often used for such a purpose. Data were collected on the food of chicks, breeding success, and chick neglect at a colony in south-east Scotland every summer in the period 1986–1996. Breeding success declined significantly over the period and breeding became later. In one year, many adults failed to breed. A similar decline in breeding success was also recorded at colonies over a 250–300 km section of coast in south-east Scotland and north-east England. Sandeels (Ammodytes marinus), especially 0-group fish (young of the year), made up the bulk of the diet in all years; herring (Clupea harengus) and sprat (Sprattus sprattus), waste from trawlers, and planktonic Crustacea was of lesser importance. Nesting success increased significantly with the proportion of 0-group sandeels in the diet of chicks and with the average energy value of 0-group sandeels, variables which were significantly and positively correlated. Clupeids and trawler waste were probably taken only when sandeels were unavailable. Brood neglect was not a good indicator of annual total breeding success. The decline in nesting success appeared to commence before the development of a large local industrial fishery for sandeels.