Blood parasites found in three passerine species during spring migration

Blood samples from three common passerine bird species, Robin, Redstart and Lesser Whitethroat, were collected during spring migration in the south-western archipelago of Finland. A total of 10 parasitic haemosporidian and trypanosomid species were recorded. The proportion of parasited samples of all three bird species was 18.0%, with no significant differences between them. Furthermore, the prevalence of parasites did not differ between the sexes in Redstarts and between age classes in Robins and Lesser Whitethroats. Instead, species that belong to the same family (Turdidae: Redstart and Robin) were partly infected with the same parasite species. The Lesser Whitethroat, belonging to the family Sylviidae, was infected with different blood parasite species compared with the Turdids. Our results indicate that during migration, the prevalence of blood parasites is rather low and that the taxonomic relationships of bird species is related to their parasitic fauna.