I've been traveling down the NSW South Coast and so have been hearing lots of birds. I'm not a tweeter but I know a few bird calls.
The oystercatcher is definitely one of them. First you hear the call and then you see them walking away from you at the same speed that you are walking. They are definitely characters of the bird world.
I'm in Eden at the moment and the air is full of the calls of bellbirds, it's a very pleasant sound (except if you are with a video crew recording people talking, which occurred to me last year).
I'm enjoying your bird photos, keep up the good work.
cheers,