Fig. 3

Relationship between roughness (Ra) and ontogenetic stage. The observed qualitative roughness patterns are positively correlated with the Ra values, and coincide with the proposed shifts in growth rate known for modern birds. The dashed line corresponding to the post-natal nutrient shift is hypothetical. The error bars represent 2σ and show relatively high ranges most likely due to the chosen ontogenetic classes still containing relatively variable roughness values (especially the intermediate classes such as chicks and juveniles, see Discussion)