Extra-pair copulations and mate guarding in the polyterritorial pied flycatcher, Ficedula hypoleuca

1. Seven out of 24 observed copulations (= 29% ) in the pied flycatcher were extra-pair copulations (EPCs). There was no significant difference between EPCs and pair copulations (PCs) with respect to timing and duration, possibly indicating that both are equally successful. Thus, proportion of copulations may reflect share of paternity. 2. Females usually do not solicit EPCs and often try to avoid them. We cannot find that females have much to gain from EPCs, while attempts to resist forced copulations may impose some costs. The fact that EPCs still are rather frequent suggests that it might be cheaper for a female to accept an EPC than to resist it. 3. Males spend much of their time mate guarding but the distance between pair members is longer for polyterritorial males than for monoterritorial males. Still, we cannot find any significant differences in risks or possibilities of EPCs between males of different mating status. However, the relaxed mate guarding by polyterritorial males suggests that these males might take higher risks, and they also suffer more territory intrusions. 4. It is most likely that male reproductive strategies are not maintained as a frequency-dependent mixed ESS with equal pay-offs for all paired males. Instead, male strategies are conditional on phenotype and breeding circumstances.