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ABSTRACT
The diet and growth of great cormorant (Phalacrocorax carbo) nestlings were studied in the Axios Delta, Greece in 1993 and 1994. The diet, based on analyses of regurgitations, consisted of fish from 12 families. In both years, the dominant prey were the goby Gobius jozo and mullets (Mugilidae). There were changes in number and wet-biomass prey composition during the study, probably due to the opportunistic foraging behavior of the birds. Most prey occurred in aquatic environments at all salinity levels, consisted mainly of benthic fish, and had no particular economic value. The growth of great cormorant nestlings was analyzed using a modification of the method proposed by Ricklefs and White (1975). Sets of estimated values for all variables studied (tarsus, bill, bill+head, and weight) plotted against age yielded sigmoidal curves. The increase in all growth variables over time was best described by the logistic equation. Body weight and tarsus increased at similar rates, and were faster than those for the bill and the bill+head measurements. The inflection point was reached by the tarsus, bill, bill+head, and weight at 10.0, 15.7, 13.5, and 18.6 days, respectively. The potential adaptive significance of this growth pattern is discussed.