timbo: I don't have time to go through all 200+ images, but had a look at the first couple of pages...
Make more use of the basic rules of composition: Rule of thirds and golden points.
Draw two horizontal and two vertical lines in your viefinder whith your imagination to divide it up in thirds, then place things along those lines and on the intersection points. Animal eyes are usually an easy one to place on an intersection point.
Then clipping ears, beak-tips and tails should be avoided. If it can't be avoided then get a little more 'creative' with the composition and rather clipp it completely to benefit the composition then just clipping the tips. Give the animals space to move into. Don't place the nose tip right on the edge of the image, leave some space infront of the animal and less space behind it.
Try to avoid shooting animals nearly completely covered by vegetation, when waiting a few seconds will give you a clear shot. Like the Giraffe shot. Giraffes don't usually disapear quickly after you spot them and stop the vehicle, like some other animals. Spend a little more time and wait for the 'nice' shots.
Good wildlife photography takes a lot of patience.
With the Hornbill series, I would have composed with less of the back of the head or top of the head (depending on the angle) and rather gotten the tip of the beak in. Except when you compose creatively and go for a shot focussing on the eye and then crop "most" of the beak instead of just the tip.
There are quite a few where your composition is making use of the basic rules, just try and keep it consistant throughout.
Zebra: Picture 018 : Rather dont clip mouth and ears. Turn the camera and do a portrait shot instead of landscape and you'll get the ears and mouth in.
Zebra - Uploaded on Sep 9, 2009 - is really not a good shot: even post processing cropping won't improve this shot, because the mouth is clipped as well as the ears.
I know it might sound only like negative comments, but thinking about composition will drastically improve your pics. I don't know if the ones that are nicely composed was thought about or just 'lucky' point and shoot.
My advice would be... Instead of racing through the bush trying to photograph as much as you can spend a day or to to just focus on improving your composition by thinking about it. When you encounter animals that look like they won't be racing off, switch the car off and don't rush yourself to shoot of as many images as you can. Spend some time to 'think' about the composition of each image. Think to yourself... don't clip noses, ears, beaks, unless I'm doing it very specifically for creative effect. If I can't get the shot horizontal, will a vertical maybe work??? Draw those third lines in your mind through your viewfinder and experiment with placing things on the intersections or on the lines, especially eyes on intersections and horizons on the lines.
Then after each image, look at it on the screen and see if the composition worked and if you missed something that you did not notice through the viewfinder, then go for the next pic.
The more you practice this, the better your composition will get when you do just pick the camera up and just shoot... Because your brain is then putting all those things into place in a split second.
But most off all... Enjoy being in the bush