EN
The food composition of goosander was determined based on the stomach contents of dead birds found along the San River between the localities of Zwierzyn and Lesko on February 12-14, 2012. The food composition of six birds was determined. The number of birds feeding in the study area was estimated to be between 0.7 to 11 individuals per 100 m of the river. The dominant prey of the goosander were brook trout (90.2% of the sample at a weight share of 80.7%), and European bullhead (70.2% of the sample at a weight share of 16.8%). The size of the trout identified ranged from 8 to 28 cm, while that of the bullhead was from 12 to 14 cm. The food biomass consumed by the birds during the period studied was determined to be 310 kg 24 h-1.