Prevailing weather conditions and diet composition affect chick growth and survival in the black-legged kittiwake

To identify priorities for management of seabirds during the breeding season, it is important to understand the ecological mechanisms driving chick growth and survival. In this study, we examined the effects of diet and prevailing weather on the growth and survival of chicks of black-legged kittiwakes Rissa tridactyla over a 10 yr period at Anda, a seabird colony in northern Norway. We show that across all years, there was a significant effect of diet composition delivered to chicks on their growth and survival. A higher proportion of sandeel Ammodytes spp. in the chick diet was associated with an increase in daily growth rates, a pattern that was especially pronounced for the youngest chick in 2-chick broods. A high proportion of mesopelagic fish in the chick diet was associated with a decrease in survival, again, especially for the youngest chick in 2-chick broods. Periods of strong southerly winds also led to reduced survival, probably linked to nests being washed down from the colony. Growth rates of kittiwake chicks were negatively affected by wind speed, likely due to adults having to work more in the exposed habitats in strong winds, causing a reduction in the amount of food supplied to the chicks. Our results emphasise the importance of conservation of specific marine habitats shown to be important foraging areas in ensuring the reproductive success of seabirds. This might prove increasingly important if future climate regimes make ecological conditions more challenging for seabirds.