Begging in avian nestlings is a highly conspicuous behavior with important implications for the study of parent--offspring conflict. In some species, nestlings also call for long bouts in the absence of parents, and it has been proposed that this behavior is used by nestlings as a means of...

Secondary sexual characters have been hypothesized to reveal the ability of males to resist debilitating parasites. Although such reliable signaling of parasite resistance may be maintained by parasite--host coevolution, maternal effects potentially provide a previously neglected factor that...

The field of androgen deposition in avian eggs and its consequences for offspring development has received a lot of attention in recent research. However, although variation within clutches in yolk androgens is relatively well understood, the adaptive significance of patterns of variation...

Mothers can influence the phenotype of their offspring by adjusting the quality of their eggs in relation to sex and reproductive value of the progeny. Maternal androgens in the eggs of vertebrates may mediate such adaptive early maternal effects. However, the evolution of early maternal effects...