To a yank like myself, Kiwis are completely mysterious. They're part of a group of birds called ratites, which includes ostriches, emus, and rheas. I tell my classes that Kiwis use their long bills to probe the ground for arthropods.
Apparently, kiwis have a side to them that was unknown to ornithologists. Apparently, like many many organisms, they enjoy bird eggs. In this case, the New Zealand Robin was the victim.
Here is a link to the video http://phys.org/news/2015-12-footage-captures-kiwi-robin-revealing.html