Figure S5. Luminance plots

Boxplots of luminance measurements obtained from plumage patches with <0.05 luminance reflectance: (a) mantle, (b) throat, and (c) black of head. Hue measurements were excluded from these patches because very dark colors yield random hues when converted into opponent colorspace. Each box is bounded by the first and third quartiles, and plot whiskers extend to 1.5 times the interquartile range or to the maximum and minimum value, as appropriate. Data points outside the whisker range are represented by open circles.