How does a kiwi bird lay its eggs?

Female kiwi lay their first egg when they are 3-5 years old. Males reach reproductive age at 18 months, but in their native habitat, they tend not to breed until they older. Breeding season begins in June, the New Zealand winter, and continues through to about March of the following year.

Kiwi dig a burrow for the egg, or find a pre-existing burrow, several months before it is laid. Three weeks after mating, the female lays an egg which is about 6 times the size of an egg from another bird of similar size. Just before the egg is laid, it makes up 15-20% of the kiwi's body weight, and takes up so much room that the female is unable to eat because there is no room in her stomach.