I've had a quick butchers through your gallery as well (finally got round to it) and left some comments.
Generally your technique is pretty good. The thing that I noticed (and I saw comments to the same effect) was backgrounds and composition. Like lots of us, you have a tendency to forget the background to a shot or to crop out something at the edge of the frame.
For example...
Mark (Cutter) has already commented about the people in the background. It's really difficult sometimes because you tend to concentrate only on the main subject of the shot, especially when it's wlidlife as they move quickly and it's about grabbing the shot. With this sort of shot, I would try desaturating the background a but and perhaps adding a vingette. That should help keep the focus on the bird.
Ignoring the background (which is difficult as it's busy), I posted this one as an example of cropping. The elephants foot is chopped off on the right side of the frame. The ideal placement would be right in the corner (but not cropped out) so it was as if he was climbing right towards you.