Fig. 4. Length of skull (A), tarsus (B) and wing (C) as a function of age, as well as growth rates of the skull (D), tarsus (E) and wings (F) as a function of the body mass growth rate in control fed (filled symbols, N=5) and diet-restricted nestlings (open symbols, N=7) kept in the laboratory. The regression line of a logistic growth curve calculated from 1050 biometric measurements of nestlings fed by their parents in the colony is shown for comparison in A–C. In D–F, the growth rate of a sample of eight nestlings fed by their parents in the colony, of which we had biometric measurements at the age of 12 and 16 days, is shown for comparison (open diamonds). The growth rates were calculated for the period from the age of 12–16 days. Values are means ± 1 S.E.M.