Diurnal cycle of Isospora spp. oocyst shedding in Eurasian blackbirds (Turdus merula)

Abstract

Diurnal fluctuations in the appearance of parasites have been recognized for more than 60 years but have been largely ignored in studies examining the role of parasites in connection with evolutionary aspects of behaviour, ecology, and population dynamics. The disregard of diurnal fluctuations, however, can influence the reliability and interpretation of data. I examined shedding of Isospora spp. oocysts in faeces of naturally infected, free-living Eurasian blackbirds (Turdus merula L., 1758). Adult birds and nestlings shed coccidian oocysts (Isospora spp.) predominantly in the afternoon. The results are in agreement with earlier studies on coccidian oocyst shedding in other bird species. They are discussed with regard to these studies and to practical implications for future investigators in this field.