Which Birds Lay The Largest And Smallest Eggs?
The elephant bird (Aepyornis maximus), an extinct flightless bird of Madagascar, also known as the "giant bird" or "roc," laid the largest known bird eggs. Some of these eggs measured up to 13.5 inches (34 centimeters) in length and 9.5 inches (24 centimeters) in diameter. The largest egg produced by any living bird is that of the North African ostrich (Struthio camelus). The average size of this bird's egg is 6 to 8 inches (15 to 20.5 centimeters) in length and 4 to 6 inches (5 to 15 centimeters) in diameter.
The smallest mature egg, measuring less than 0.39 inches (1 centimeter) in length, is that of the vervain hummingbird (Mellisuga minima) of Jamaica.
Generally speaking, the larger the bird, the larger the egg. However, when comparing the size of the egg with the size of the bird, this does not always hold true. The ostrich egg, for example, is one of the smallest eggs relative to the bird's body size. And the hummingbird egg is one of the largest eggs relative to the bird's body size. The Kiwi bird of New Zealand lays the largest egg relative to body size of any living bird. Its egg weighs up to 1 pound (0.5 kilograms).
Sources: Cruickshank, Allan D. 1001 Questions Answered About Birds, p. 174; Walters, Michael. Birds' Eggs, pp. 12-13; Wood, Gerald L. The Guinness Book of Animal Facts and Feats, pp. 90-91.