Linear mixed model explaining background reflectance of yellow breast feathers in Great Tit nestlings.

For fixed effects, type 3 tests and denominator DF are presented, numerator DF = 1 in all cases. For random effects, covariance parameter estimates are presented (REML method). Likelihood ratio test of the overall significance of random effects: χ2 = 39.9, DF = 3, P<0.001. P-values of significant factor are in bold. *Estimate for 1y old (relative to older) females. **Estimate for reduced (relative to enlarged) broods. ***PC1 of yolk antioxidants included concentrations of vitamin A, vitamin E, lutein and zeaxanthin in egg yolk; all concentrations were log10-transformed.