WEIGHT-GAIN OF BLUE-FOOTED BOOBY CHICKS - AN INDICATOR OF MARINE RESOURCES

Chicks of blue-footed boobies were weighed and measured at 13 localities in the Galapagos Archipelago [Ecuador] during July 1981. Chicks were reweighed and remeasured after 5 days. For data analysis, individuals were divided into 4 size groups based on wing length, within which initial weights were adjusted with respect to wing length, and weight increments were adjusted with respect to wing length and adjusted initial weight. Both adjusted initial weight and adjusted weight increment exhibited significant heterogeneity among breeding localities. In general, rapid growth was associated with cold, productive water in the western part of the island group, but adjusted initial weights indicated that growth performance immediately prior to the beginning of our study exhibited a different geographical pattern. The results show that growth of seabird chicks may provide an indicator of feeding conditions useful to oceanographers, ecologists and resource managers. Each species of seabird will be sensitive to a different part of the marine environment, thus enabling researchers to assess the condition of many marine resources independently.