Honestly....it calls "Muuuuuum!" in DD's voice! It's got her Aussie accent and everything! We live in Australia but come from the UK....moved her 4 years ago.
I heard it and thought it was DD! Realised she wasn't calling me and there it was "Muuuuum!"
I don't know what bird it is. We have magpies which are very good at imitation locally....one on the news neighs like a horse.
I think this is clear evidence that DD calls me in that irritating way FAR too often! I've pointed it out to her as evidence of this. She's 11 and doesn't care.