It is really funny with these birds, on some places they are shy as hell and if they see you from 1000 meters or more they are already fleeing, and it is impossible to get close enough for a picture. But on other spots I know, they don't really care about humans, and I was able to get several nice pictures of them.
I think It really depends heavily on the fact that these birds were hunted down on several places and therefore are shy as hell. And on other places nobody hunted them and they are not afraid of humans at all.
Yes, most likely it is, you are right. Cool pictures!