Male quality measures in relation to vocal deviation and trill consistency, with effects that remained significant after correction for multiple testing in bold.

Trill measures were the dependent variables, and male quality measures were the independent variables, in mixed-effects models controlling for male identity, year, trill type, pitch, trill duration, and the time of the trill in the song. For age, the effect estimate is the difference between second-year and after-second-year males, and the effect size is Cohen’s d. For continuous variables, effect estimates are the slope, and the effect size is partial r. Song rate, flight rate, and time close are responses to playback. Abbreviations : Voc Dev: Vocal Deviation. H:L, Heterophile:Lymphocyte ratio. Bact Cap, Bactericidal Capacity. CI, Confidence Interval.