Fig. 2. Changes in yolk-free wet mass (g) of pelicans and in yolk mass (g) with respect to relative incubation age, where 1.0 is the hatchling on day 33 of incubation. Asterisks refer to wet yolk, triangles to pre-internal pipping embryos (N=6), filled circles to internally pipped embryos (N=4), diamonds to externally pipped embryos (N=4) and open circles to hatchlings (N=14).