If you can id a shrike from that picture you must know your stuff!! I only put it on for a laugh - though it does show the weakness of relying on AF. Both taken with a Sony superzoom btw.
I've not done a huge amount of walking in the bush - we have stayed a few times at a small camp in the Klaserie (part of the Greater Kruger - so no fences between this area and the Kruger), and the guys we stayed with are both into walking rather than vehicle based safaris so we tend to walk in the mornings, for two to three hours, generally with a purpose, say tracking rhino or lion. So - one has to walk very carefully to minimise noise, which, in SA winter is hard work as everything is so dry and one is off trail/path 99% of the time. But a fabulous experience to be in the bush surrounded by wildlife - had some amazing moments.