Energy budget and foraging behaviour of the Cape gannet Morus capensis during the breeding season

Includes abstract.Includes bibliographical references.This thesis deals with the energy expenditure of free-ranging Cape gannets Morus capensis breeding at Malgas Island, South Africa. I sought to determine the energy budget of family units and to extrapolate this to the whole population. Energy expenditure was measured using the doubly labelled water technique on adults and chicks. CO2 production was determined from ratios of isotope turnover, and converted into energy expenditure using a factor suitable for a fish-eating seabird