Hi Linda,
compositionally wise ...
I think the first is composed well. The bird is all in the frame, but takes a fair component of the total frame. It is even looking at the camera, which has got to be a bonus.
The dragon shot is OK too. I personally would have liked to see the whole dragon in the shot.
Looking at the exif for your shots (I use firefox, and have downloaded the addin FxIF, which shows the exif when you right click on a photo - if the photo has been stored with the exif info), you have used a very low shutter speed at ISO 100. The first 1 says 1/20 second at 130mm. Unless you have pretty stable hands (and/or) a VR lens, you will probably get some camera shake at that speed.
As others have mentioned before, I would recommend pushing the ISO up to at least 200, maybe 400. That should help you get a bit quicker shutter speed (if the light is poor). I shoot at 200 ISO most of the time on my D80, and very rarely go below that.
For your trip to Australia Zoo tomorrow, maybe put the camera in "A" (for aperture)
mode, dial the ISO up a bit, and set the aperture where you want for the effect you are after.
Ohh Yeah ... Have fun. I am sure you will have a ball, learn some things and come home with some photos you are happy with. As long as you are striving to get better, and learning each time you go out, what more can you ask for.