Effects of spatial and host variables on hematozoa in white-crowned sparrows wintering in Baja California

A survey of blood parasites was conducted in February 1995 on white-crowned sparrows (Zonotrichia leucophrys) wintering in two environmentally differe nt localities of Baja California Sur (Mexico). Blood parasite prevalence wa s higher in La Purisima (49%) than in San Jose del Cabo (8%), but there wer e no differences between ages or sexes within each locality. All haematozoa n infections were by Haemoproteus coatneyi, except one bird in each site th at were positive for Trypanosoma sp. We found no evidence for the predicted negative relationship between host body condition and intensity of parasit ism. The relatively high prevalence in one site suggests that ari increase of hematozoa transmission may occur in that area.