Gilly Akers, of Wellington, asks :-
Why have pukekos survived and flourished when the other ground birds haven't and are killed by stoats and cats?
John Craig, a zoologist with Green Inc, responded.
Pukeko are large and are only vulnerable when young. Their nests are typically surrounded by water and chicks can spend a lot of time in wet areas which are not preferred by most mammals excepting Norway rats.
In addition, pukeko typically live in groups so there are many eyes to detect predators. In addition, when attacked all of the group join the fight. I have seen a group of pukeko actively attacking a Norway rat and if they had caught it they would then have eaten it.
All of this gives them an advantage over other birds. Furthermore they typically have a large number of eggs in their nests (if there are too many for one bird to cover, they will have two nests side by side. While they have anything from 5 - 18 eggs in a nest, it is rare for them to raise more than 5 young at a time. They can have 2 - 4 broods a year so even if they lose many of their young, there are always more produced than would die in a year.