Repeatability of Daily Energy Expenditure in Black-legged Kittiwakes (Rissa tridactyla)

This projects’ main objective is to investigate whether daily energy expenditure (DEE) measurements of chick-rearing kittiwakes, are repeatable within and between years, i.e. if there are individuals with consistently high or low energy budgets and how these individuals differ in reproductive investment and behaviour. By standard DEE measurements in wild birds have been done over a period of 24 hrs. If animals do not budget their energy expenditure accordingly, a high day-to-day variation in DEE might occur. This project wishes to increase that period to 3 days, thereby testing the underlying assumption that many, if not most, studies in animal energetics imply: that DEE estimates derived by the DLW method represent the long-term level of energy expenditure of the measured individual . The high variability found in Kittiwakes has to date largely been attributed to time spent on various activities, such as foraging and nest attendance. Repeatability of DEE is however of paramount importance to interpret these data. If individual variation over longer time periods (3 days) is consistent, DEE can be a good proxy for the long-term energetic effort of individuals and their parental effort. The doubly labelled water (DLW) method will be used to measure daily energy expenditure. The fieldwork conducted in 2011 will be the main basis of my MSc thesis and results will be also be integrated as part of a larger project on energetics and oxidative stress in adult kittiwakes.