Parental care typically involves elaborate reciprocal within-family interactions, and traits such as parental provisioning and offspring begging should therefore coevolve. There is indeed mounting evidence for a phenotypic covariation, also in the canary (Serinus canaria), our model species. Such covariation may arise due to maternal effects, rendering this relationship particularly sensitive to environmental conditions. Here, we manipulated the social environment by pairing females with either their chosen or non-chosen male. Subsequently, all clutches were cross-fostered to separate pre- and postnatal effects. We found a positive covariation between offspring begging and parental provisioning, which was, however, unaffected by mate preferences, and we found no evidence for differential allocation. In addition, there was no effect of assortative mating, which is thought to reinforce parent–offspring covariation. The fact that parent–offspring covariation is consistently observed in canaries suggests that it is biologically relevant, but it requires further studies to elucidate its sensitivity to environmental variation.
Migratory constraints on yolk precursors limit yolk androgen deposition and underlie a brood reduction strategy in rockhopper penguins