Costs and benefits of early reproduction: Haemoproteus prevalence and reproductive success of infected male pied flycatchers in a montane habitat in central Spain

Laying date is a key factor in avian reproductive ecology. Benefits of early breeding are important in terms of reproductive output. Costs are mainly associated to weather adversities at early stages of the breeding season. As males arrive earlier than females, they may face these weather adversities more frequently and therefore suffer higher costs at early stages of the season. We studied the potential association between the prevalence of infection by Haemoproteus, condition and age with the breeding phenology in male pied flycatchers Ficedula hypoleuca in a montane population in central Spain. Early males benefited from a greater reproductive success, but they may have paid costs in terms of a more marked seasonal relapse from Haemoproteus infections.