Clinico-pathological examinations were conducted on wild white-winged
scoters (Melanitta fusca) contaminated with fuel oil (Bunker C oil) fr
om a capsized cargo ship in February 1993 in Japan. The erythrocyte co
unt, hemoglobin concentration and hematocrit value in the oiled seaduc
ks all were decreased and numerous immature erythrocytes were observed
in blood smears. In addition, hemosiderosis was observed in the liver
, kidney, and lung of some birds. We propose that the seaducks suffere
d from hemolytic anemia induced by ingestion of oil, which occurs when
the birds preen their oiled plumage.