Incidence of a Haemoproteus lari parasitemia in a threatened Gull: Larus audouinii

Abstract

Data on haematozoan parasitemias in Laridae are scarce and, since blood parasites may influence birds fitness, it is important to report their incidence in threatened species such as Audouin's Gull . Blood smears of 90 Audouin's Gulls caught during incubation at theirtwo main breeding sites, the Ebro Delta and the Chafarinas Islands, were examined for Haemoproteus lari parasitemia. Overall prevalence of the parasite was 92.1% for the Chafarinas Is . and 28.9% for the Ebro Delta. To our knowledge, prevalences reported in this study are the highest ever recorded for Laridae. Differences in prevalence between localities were significant, but not differences between the sexes within each locality . Males were more intensely parasitizedthan females in Chafarinas, andgulls from Chafarinas were more intensely parasitized than those from the Ebro Delta. Differences in intensity were also checked using data from sympatric Yellow-legged Gulls, L. cachinnans, and only the factor locality was significant. There was no significant relationship between body condition and intensity of parasitemia in males or females in either locality . These data indicate higher susceptibility to H. lari for gulls breeding at the Chafarinas Islands.