@Junklekitteb They were basically always around one carcass - a Gaur that had been taken down by a Tiger - so we saw them very reliably if we went past it and not at all if we didn't.
As well as decent numbers of White-rumped there were a couple of Red-headed around as well but they were less showy and I only managed distant flight photos.
@Maguari That maybe explains why I’ve never seen them then, never come across a carcass on a safari.
Good to hear that you got to see the red-headed. I would dare say they’re probably the rarest animal that can be seen at the park (unless there’s some obscure insect I’m unaware of).