I've heard it calling in the back yard for several days. I was puzzled as it sounded like an aviary bird but no-one has one near here Today I tracked down the source. I hadn't heard a Grey Currawong call before.
Not sure what you mean, but over the several days it has made different calls. I did take a movie of it yesterday to capture the call (the neighbours kids can also be heard though). Yesterday it was mostly making a two note call, similar to what a budgie also makes.
The call in the first example is the one I hear most often. In fact it was just calling again. I'm sure I've heard other calls but before I worked out what was making the calls.