Which country is home to the kiwi bird?

New Zealand, which spent about 80 million years as an isolated set of islands with no land mammals at all. Birds took the jobs mammals do elsewhere - grazing, browsing, hunting on the ground - and several stopped bothering to fly, since there was nothing to fly away from.

The kiwi went furthest. It is roughly the size of a chicken, nocturnal, with hair-like feathers, whiskers, marrow in its bones instead of the hollow structure other birds have, and nostrils at the tip of its beak rather than the base - it is the only bird that finds food by smell, snuffling through leaf litter for worms.

It also lays an egg of ludicrous proportion: up to about a fifth of the female's body weight, one of the largest relative to body size of any bird. The chick hatches fully feathered and essentially self-sufficient. The vulnerability is exactly the one you would predict - stoats, rats, cats and dogs were introduced by people, and a bird that evolved with no ground predators had no instinct for any of them.