Female hematozoan infection reduces hatching success but not fledging success in Pied Flycatchers Ficedula hypoleuca

We report association between female blood parasite prevalence (percentage of infected birds) just after egg laying and reproductive success in two su ccessive breeding seasons, in a breeding population of Pied Flycatcher Fice dula hypoleuca in central Spain. Females infected with Trypanosoma spp. had a higher probability of deserting their clutches during the incubation per iod than noninfected females. Females infected with Haemoproteus balmorali hatched proportionally fewer eggs than noninfected females. Female infected With H. balmorali during the incubation period may have a decreased abilit y to thermoregulate which may a ect their incubation capacity. Fledging suc cess, breeding success, fledgling mass, and tarsus length were not associat ed with infection of the mother by blood parasites during the incubation pe riod, suggesting that females and their mates may compensate during the nes tling period for the negative effect of blood parasites during the incubati on period.