Figure S4. Morphometric plots

Boxplots of morphometric size variation among subspecies of the varied tit (Sittiparus varius) complex: (a) bill length, (b) bill depth, (c) bill width, (d) tarsus length, (e) wing chord, and (f) tail length. The taxon castaneoventris showed non-overlapping size variation in bill depth, wing chord, and tail length. Heavy lines inside boxes represent the mediums (second quartiles). 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.