REGULATION OF FOOD PROVISIONING IN THE ANTARCTIC PETREL THALASSOICA-ANTARCTICA

1. Life-history theory predicts that individual birds should invest in reproduction according to their current body condition and the future prospects for survival and reproduction. Thus, it could be expected t hat current adult body condition should significantly influence food p rovisioning rates, food loads and concurrent chick growth in the Antar ctic petrel. 2. In order to study the significance of parental body co ndition I correlated meal sizes, feeding frequencies and chick growth with the body condition of the parents. 3. There was a strong correlat ion between the average meal size delivered to a chick and its growth rare. Adult body condition at the time of hatching was strongly correl ated with the average size of meals delivered to individual chicks. Ma le and female body condition at the time of hatching and average body condition of the pair at the first incubation shift and at hatching si gnificantly influenced the body mass of the chick on day 30. Male body condition and the average body condition of the pair correlated signi ficantly with the growth rate of the chick. 4. The difference in body mass at the age of 30 days of chicks from parents with good body condi tion compared with chicks from parents with poorer body condition was nearly double that expected. 5. The results strongly suggest that the effort spent during the chick-rearing period, and thus reproductive su ccess, is regulated by the body condition of the parents.