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

This study reports effects of experimental manipulations of reproductive ef fort and the size of the male's white forehead patch (a secondary sexual tr ait), on provisioning rates, reproductive success, and parental breeding di spersal 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 fore head patch fed their nestlings more in relation to males with an unmanipula ted forehead patch, and their young fledging with a longer tarsi. This sugg ests that males with a reduced attractiveness may perceive their own attrac tiveness and they devote more rime available for parental effort given thei r poorer prospects in male contest competition and/or female attraction for extra-pair copulations. However, their females did not alter their provisi oning effort and this runs counter to both the differential allocation and the partner-compensation hypotheses. An artificial decrease in a male secon dary sexual trait led to a wider breeding dispersal distance between succes sive pears.