Diet and growth of chicks of the Great Cormorant, Phalacrocorax carbo, at Ramsar, northern Iran (Aves: Phalacrocoracidae)

Abstract

The diet of Great Cormorant (Phalacrocorax carbo Linnaeus, 1758) chicks was studied using regurgitated fish prey in a colony at Ramsar, northern Iran, in the 2003 breeding season. The development of young was analysed in terms of body mass and wing length growth. The regurgitated prey items belong to Gobiidae, Mugilidae, Atherinidae and Clupeidae, with approximately 90% of the regurgitated prey mass belonging to Gobiidae and Mugilidae. The growth rate, expressed as body mass increment per day during the period 1–30 days, ranged from 58.7 to 112.2 g/d and was independent of age ranking and brood size. The growth rate of wings was 5.5 to 8.2 mm/d and did not vary between broods of different sizes and chicks of different ages.