Sexual differences in the diet of great cormorants <Emphasis Type="Italic">Phalacrocorax carbo sinensis</Emphasis> wintering in Greece |
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Authors: | Vasilios Liordos Vassilis Goutner |
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Institution: | (1) Department of Zoology, School of Biology, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece |
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Abstract: | Sexual differences in the diet of the great cormorant, Phalacrocorax carbo sinensis, were studied in four Greek wintering areas, the Amvrakikos Gulf, the Axios and Evros Deltas and the Messolonghi Lagoon,
through the analysis of stomach contents. Great cormorants are birds sexually dimorphic in size, with males being generally
larger than females. Although similar prey species were found in the stomachs of both sexes in all the studied areas, significant
differences were observed with respect to the proportion of species taken. Male birds ate higher proportions of large fish
species such as grey mullets, European sea bass, Dicentrarchus labrax, and Prussian carp, Carassius gibelio, while female birds took higher proportions of smaller species such as big-scale sand smelt, Atherina boyeri, and black goby, Gobius niger. As a consequence, male great cormorants were found to feed on significantly larger prey than did females by means of fish
standard length and body mass. There was no significant difference between the sexes in the mass of food found in stomachs. |
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Keywords: | Piscivorous predator Winter diet Prey selection by sex |
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