Sexual differences in the diet of king cormorants at Macquarie Island

摘要

Sexual differences in the diet of king cormorants,Phalacrocorax albiventer, were investigated during the 1993/1994 austral summer at Macquarie Island. The major food items, identified by otoliths in regurgitations, were demersal fish; fish mass consumed could be estimated using a wet mass-otolith length relationship. Two fish species,Paranotothenia magellanicaandHarpagifer georgianus, constituted 98 of the wet mass (male and female cormorants combined). Estimated individual fish mass ofParanotothenia magellanica(19.6±11.6 g) was greater than that ofH. georgianus(2.8±1.3 g). Total wet mass of food and number of fish in regurgitations did not differ statistically between the sexes of cormorants. However, males tended to feed on larger fish than did female