I would agree with you Mel, there seems to be quite a large hyena population in Addo now. I think I heard something about some being moved out a while back but we don't really get to hear/see it much unlike the lions when it's really obvious when they disappear.
As for prey, i think they are surprisingly resourceful and although the northern side of the park is in drought, the southern side is fine... so a lot of herds of prey species available
