1. Seems a little underexposed, but nice shot otherwise. Normally, I'd say if you can, shoot birds from the front--the more you can get of their eyes, the better the photo, generally. However, for me, anhingas and such (not sure what you call them down under) spreading their wings are an instance where the "behind the bird" shot works.
2. and 3. These are moons. That's just really all I have to say about that. Everybody has to do a few moon shots.
I will say this: on #2, you've at least gotten a decent exposure, showing some detail. Many, many people completely overexpose their first moon shots and end up with a big white blob.
4. Love this; very nice! Is that a Kookaburra? Every time I see one of those birds, I hear this little song in my head that I learned in elementary school many, MANY years ago. It's a highly annoying song. :lmao: But a very cool bird. I'd be tempted to clone out that out-of-focus stick in the right foreground, and possibly even crop this to a portrait orientation. But it's well exposed, and you got good, sharp focus on the eye (it looks like it to me anyway--I do have vision issues so others may say differently).
5. Bee on flower--white balance seems off, on the yellow side (but wait for other opinions, I'm often wrong about wb). The composition isn't really making me love it either. I wish there was more room above the bee, and less room beneath the clover stem.
These are not a bad start at all. Keep shooting and keep posting!