Experimentally reduced male attractiveness increases parental care in the pied flycatcher Ficedula hypoleuca

This study reports effects of experimental manipulations of reproductive effort and the size of the male's white forehead patch (a secondary sexual trait), on provisioning rates, reproductive success, and parental breeding dispersal distance in the pied flycatcher, Ficedula hypoleuca. Parents caring for enlarged broods resulting from manipulated clutches provisioned nests at higher rates than parents with reduced broods. Males with a reduced forehead patch fed their nestlings more in relation to males with an unmanipulated forehead patch, and their young fledging with a longer tarsi. This suggests that males with a reduced attractiveness may perceive their own attractiveness and they devote more rime available for parental effort given their poorer prospects in male contest competition and/or female attraction for extra-pair copulations. However, their females did not alter their provisioning effort and this runs counter to both the differential allocation and the partner-compensation hypotheses. An artificial decrease in a male secondary sexual trait led to a wider breeding dispersal distance between successive pears.