Supplementary material

Table S1. Egg characteristics of bird species (length (L), maximum diameter (D), indices of infundibular (Iiz), cloacal (Icz) and lateral (Ilz) zones) and values of principal components.

Figure S1. Shape of eggs associated with different regions of specific phylogenetic principal components: minimum, mean, and maximum.

Figure S2. Position of orders in the space of PC1 and PC2. Shape of eggs correspond to specific parts of PCs. Loadings are shown at the lower left corner of the figure.

Figure S3. Position of orders with altricial developmental mode in the space of PC1 and PC2. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S4. Position of orders with precocial developmental mode in the space of PC1 and PC2. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S5. Position of orders with semialtricial developmental mode in the space of PC1 and PC2. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S6. Position of orders with semiprecocial developmental mode in the space of PC1 and PC2. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S7. Position of orders in the space of PC2 and PC3. Shape of eggs correspond to specific parts of PCs. Loadings are shown at the lower left corner of the figure.

Figure S8. Position of orders with altricial developmental mode in the space of PC2 and PC3. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S9. Position of orders with precocial developmental mode in the space of PC2 and PC3. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S10. Position of orders with semialtricial developmental mode in the space of PC2 and PC3. Outlines of eggs for each order is given around the perimeter of the main plot.

Figure S11. Position of orders with semiprecocial developmental mode in the space of PC2 and PC3. Outlines of eggs for each order is given around the perimeter of the main plot.