The Kiwi is a real Natural Oddity. It may be a bird, but it fills the niche of a mammal. Its body temperature is lower than most birds, and its feathers are made of loose fillaments, not interlocked ones, like most birds. It cannot fly - doesn't even have wings to speak of. it prods with its bill in the leaflitter, searching for bugs and grubs, clearing its nostrils by snuffling. It is the only bird with the nostrils at the tip of its beak. Kiwis are monogamous, and the egg is the largest in proportion to any bird*. Once the female has laid the egg, she goes off to eat (she's had to eat a lot to help the egg production and then fast towards the end because her stomach is compacted due to the egg) and the male does the incubating (in almost all the species). The chick that hatches is a miniature kiwi, almost ready to fend for itself.
* In Port Douglas the guide there declared this particular "claim" true of the Brush Turkey of Australia . It's not. Brush Turkey eggs weight 180 gms and the average weight is 2274 gm (less than 10% - 8% to be precise). However, the Brush Turkey can lay more than 3 times its weight in eggs.
The brown kiwi on the other hand, lays one egg weighing 450 g, whereas she weights around 2800 gm (making the egg 16%).