Why is the ostrich egg smallest relative to its size?

The ostrich egg is relatively small for the size of the bird due to evolutionary adaptations. Larger birds typically produce larger eggs, but the ostrich's egg size is optimized to balance the needs for embryo development and the physical constraints of the bird’s body. This size allows for efficient nutrient storage while ensuring the egg can be laid and incubated effectively. Additionally, smaller eggs may reduce the risks of predation and facilitate easier movement and care by the parent.