Statistical models describing seasonal achromatic changes (ΔL) over the year.

Significant variables are depicted in bold. For the two studied patches where there was a significant sex*month or sex*month2 interaction males and females were analysed separately (sex*month2, back robin F1,215.3 = 5.06, p = 0.025; sex*month; crown blackbird, F1,119.9 = 7.13, p = 0.0086; all others p>0.1).
*analysis carried out on Box-Cox transformed variables to improve normality of residuals. Note that here effect sizes cannot be directly compared with those of untransformed variables.