List of bird species (Common and Latin name) used in sampling of NISC (description of colour and area on the body where feather was sampled); Details of melanosomes sampling from E. brachyptera fossil and results of their measurements; Trait database used for Ancestral state reconstruction and posterior probabilities of colour state for E. brachyptera; Posterior probabilities of colour state for E. brachyptera; 1000 phylogenetic trees downloaded from birdtree.org in Nexus format; Tukey's post-hoc test results (pairwise comparison); Forward stepwise regression results and plot of the first two variables; Li et al. database with measurements of melanosomes isolated from feathers expressing non-iridescent structural colour included. Added samples are indicated with blue colour in the database.; Results of simulation of correct classification of colour categories with quadratic discriminant analysis; Figure 2D, figure 2E, figure 2F, figure 2G, figure 2H - melanosome extraction details

We have uploaded separate file in the Step 3 section where we have listed entire content of our Supplementary material.