Fig. 4: Heritability of chromatic (PC1, PC2) and achromatic (L) components of colour variation in five plumage patches of male purple-crowned fairy-wrens (posterior mean values obtained using MCMCglmm).

PC2 of the purple crown colouration and PC1 and PC2 of the blue tail colouration show moderate to substantial heritability. Error bars depict the 95% credible intervals. Also indicated (in brackets) is the proportion of chromatic variation explained by each PC for each patch colour. Purple: higher PC1 = higher UV/blue reflectance relative to green/red, higher PC2 = higher red reflectance relative to green and higher blue reflectance relative to UV, i.e. more purple overall; blue: higher PC1 = lower red reflectance relative to UV, blue and green, higher PC2 = higher UV, blue and red reflectance relative to green/yellow; buff-white and brown: higher PC1 = higher UV and lower red reflectance.