Maternal glucocorticoids are known to affect offspring phenotype in numerous vertebrate
taxa. In birds, the maternal transfer of corticosterone to eggs was recently proposed as a
hormonal mechanism by which offspring phenotype is matched to the relative quality of the
maternal environment. However, current hypotheses lack supporting information on both
intra-and inter-clutch variation in yolk corticosterone for wild birds. As such, we examined
variation in yolk corticosterone levels in a wild population of European starlings (Sturnus …