The tiny hummingbird weighs little, but its egg is 15 percent of the adult hummingbird' s weight  The volume and weight of an adult goose are much greater than those of a hummingbird, but a goose' s egg is only about 4 percent of its own weight  An adult ostrich, much larger and heavier than a goose, lays an egg that is only 1
6 percent of its own weight
The ratio of egg weight of a species to body weight of an adult member of that species is smaller for larger birds than for smaller ones.