Baseline glucocorticoids alone do not predict reproductive success across years but in interaction with enzymatic antioxidants

Glucocorticoids are known to adjust organismal functions, such as metabolism, in response to environmental conditions. Therefore, these hormones are thought to play a key role in regulating the metabolically demanding aspects of reproduction, especially in variable environments. However, support for the hypothesis that variation in glucocorticoid concentrations predicts reproductive success is decidedly mixed. Two explanations may account for this discrepancy: a) glucocorticoids might not act independently but could interact with other physiological traits, jointly influencing reproduction, and b) such an association could become apparent primarily in challenging environments when glucocorticoid concentrations increase. To address these two possibilities, we determined natural variation in circulating baseline glucocorticoid concentrations in parental great tits (Parus major) alongside two physiological systems known to be related to an individual's metabolism: oxidative status paramete..., , , # Baseline glucocorticoids alone do not predict reproductive success across years but in interaction with enzymatic antioxidants

[https://doi.org/10.5061/dryad.69p8cz997](https://doi.org/10.5061/dryad.69p8cz997)

In this dataset, you can find three files: the R code ('Mentesana_Adults_data') for the statistical analysis, as well as two Excel files ('Mentesana_Adults_db' and 'Mentesana_Chicks_db') containing information on 'adult' and 'chick' great tit (*Parus major*) samples, respectively, during the breeding seasons of 2015-2016, from a free-living population located in southern Germany.

The column names in both Excel files stand for:

* ID (both files): unique identification for the cell.
* Date (both files): the date when we captured the birds.
* Year (both files): Year of sampling.
* Nest (both files): nest where the bird bred.
* Life_history (only in the database for adults): breeding season, when chicks were 9-10 days old after hatching.
* Sex (only in the database f...