American Redstart (Setophaga ruticilla) Science Article 4
We examined American redstarts (Setophaga ruticilla) for protozoan blood parasites on their wintering grounds to determine whether transmission of these parasites occurs prior to spring migration. A total of 73 blood smears from 37 birds were examined for presence and intensity of infection. Thirty-six birds were sampled in the fall, soon after arrivingfrom northern breeding grounds, and the spring prior to departure. Two (5%) of the samplescollected in the fall were positive for Haemoproteus fringillae and one (3%) had detectableinfections of Trypanosoma avium. Individuals infected with H. fringillae were hatching year redstarts sampled in September and October. Intensity of infection was 78 and ,1 infected erythrocytes per 10,000 erythrocytes, respectively. None of the birds had detectable infections when resampled prior to spring migration the following March.
Mary C. Garvin, Peter P. Marra, and Sarah K. Crain, Journal of Wildlife Diseases, 40(1), 2004, pp. 115-118