The prevalence and ecology of the haematozoan parasites of European blackbirds, Turdus merula

The prevalence and ecology of the haematozoan parasites of a rural populati on of European blackbirds, Turdus merula, were investigated. Parasites belo nging to eight species from four genera (Leucocytozoon, Plasmodium, Haemopr oteus, and Trypanosoma) were identified. Prevalence was high: 83% of adults and 80% of juveniles were infected by at least one species of haematozoa, but no parasites were detected in 8-day-old nestlings. There were no sex di fferences in infection rates and only Plasmodium infection varied with age among adult blackbirds. Haemoproteus infections increased and Plasmodium in fections decreased through the sampling period (January to July), but infec tions with other haematozoa showed no seasonal change. Haemoproteus and Pla smodium were negatively associated with each other, even during the period when infections by both genera were frequent in the study population.