The apparent scarcity or absence of blood parasites in some avian groups, such as seabirds, has been related to intrinsic and extrinsic factors including host immunological capacity, host-parasite assemblage, and ecological parameters, but also to reduced sensitivity of some methods to detect low parasite prevalence/intensities of infection. Here, the haemosporidian parasite prevalence was examined in a breeding population of a long-distance migrant seabird, nesting in the Macaronesian...