Sex-specific effects of hatching order on nestling baseline corticosterone in a wild songbird data

Data from three studies investigating whether corticosterone mediates sex-specific effects on nestling size in house wrens (Troglodytes aedon). The data from each study are on separate tabs and a key to the variable names are located on the last tab. Corticosterone was measured via blood samples from nestlings in the “cort in first- and last-hatched” study and the “cort in cross-fostering” study and from yolk in the “cort from eggs” study. We found a significant interaction between sex and relative hatching order in their effects on nestling baseline corticosterone, but no effect of hatching synchrony. Corticosterone levels remained relatively constant across the hatching order in males but decreased in females. There was a significant effect of laying order on yolk corticosterone, with first-laid eggs containing significantly higher levels of yolk corticosterone than last-laid eggs. Cross-fostering of nestlings at different points of development had no significant effect on nestling corticosterone levels.