Feeding ecology of pelagic cormorant, Phalacrocorax pelagicus, in breeding period

摘要

The material for studying food of pelagic cormorants was collected for five summer periods in seabird colonies of the Bering Sea and the Sea Okhotsk. 746 pellets of adult birds and 384 belches of chicks was analyzed. About 41 fish species (18 families) were found in the food of pelagic cormorants. Benthal (63.4 percent) and benthopelagic (22 percent) fish species predominated. Decapoda (shrimps, hermit crabs, and crabs) occurred more rarely (46.7 percent) in the food of adults and chicks. The diet of the cormorants is different in various colonies, even in adjacent ones. Trophic links of pelagic cormorants are mainly related not to particular species of fish and invertebrates, but to certain feeding stations at the depths, to which the foraging birds dive. The fauna of a particular region probably specifies the food spectra. The diet of chicks is less diverse and is not characteristic of cormorants, even in a separate colony.