Short- and long-term effects of egg size and feeding frequency on offspring quality in the collared flycatcher (Ficedula albicollis)

1) Despite the central importance for life-history theory, egg-size effects on offspring fitness are still considered ambiguous. Most previous studies were only observational and consequently might suffer from uncontrolled correlations between egg size and parental/territory quality. Even after cross-fostering is performed, direct genetic effects and parental adjustment of postnatal care might confound our estimates of egg-size effects per se. 2) I performed a full cross-fostering experiment in the collared flycatcher (Ficedula albicollis) exchanging the whole clutches between pairs of nests. I statistically controlled for direct genetic effects and parental feeding frequencies. I followed young until recruitment to estimate the long-term effects of egg size and parental provisioning. In addition, I compared the effects obtained in the cross-fostering experiment with those obtained from a set of unmanipulated nests. 3) Egg size per se affected offspring morphology in both the short- an...