Fig. 1. Daily food intake (A) and body mass (B) as a function of age in controls (black bars and black symbols) and diet-restricted nestlings (open bars and open symbols) of European shags kept in the laboratory. The regression line of a logistic growth curve calculated from 1645 body mass measurements of nestlings fed by their parents in the colony is shown for comparison in B. Food intake is given as fresh weight of gadoid fish fillets in g day^-1. Values are means ± 1 S.E.M.