birds from the high andes in the national natural park chingaza, colombia, were surveyed for blood parasites in april 2002 and march 2003. of 136 birds examined, representing 40 species of 14 families, 38 were infected with blood parasites. parasites of the genera leucocytozoon (21.3% prevalence), plasmodium (8.1%), hepatozoon (2.9%), microfilariae (2.9%) and haemoproteus (1.5%) were recorded. twenty five avian species in this survey were examined for blood parasites for the first time and 49 new parasite-host associations were identified. the most striking observation of this study was the high prevalence of leucocytozoon spp. in the neotropics, the prevalence of leucocytozoon spp. has not been reported to be greater than 0.2% and is closely associated with the presence of migrant birds. its presence in native avian host suggests a local transmission cycle in the zone.