Fig 2. Dorsal shape variation in the upper mandible of the six-week old turkeys.

The dorsal shape variation in the upper mandible explained by (A) PC1 and PC2, and (B) PC1 and PC3 for the 2429 male (black) and female (grey) turkeys photographed at six weeks of age. The light blue beak outlines represent the mean dorsal shape of the upper mandible for these six-week old turkeys. The dark blue outlines are visual representations of the dorsal upper mandible shape at the minimum and maximum scores along the axis of each principal component.