Survey for blood parasites in redheads (Aythya americana) wintering at the Chandeleur Islands, Louisiana.

We detected no infections with species of Plasmodium, Haemoproteus, Leucocytozoon, Sarcocystis or Trypanosoma in blood smears, liver and spleen impressions, and muscle tissue from 136 redheads (Aythya americana) collected or captured at the Chandeleur Islands, Louisiana (USA), during three winters (1987 to 1990). One bird, a juvenile male, was infected with an unidentified species of microfilaria. Thus, we found no evidence that hematozoa had an effect on redheads during the course of the study.