Con
I agree that is the current situation. I am hoping that a couple of spritely younger folks (SYF - I'm sure there are some of them somewhere around the Canberra birding community) would take themselves to the wetlands such that while one searched near the moo-moos the other assessed the Azure Kingfisher (AK) situation in the Tadorns/Fulica (TF) hide area. Being SYFs I am sure they'll be fully equipped with technology to send each other photos simultaneously.
If both find an AK that shows there are two.
If only the TF hide person finds an AK that would be further evidence suggesting one bird which has moved. But how one proves that without banding and/or radio tracking I don't know.
If neither of them finds an AK that probably means there is too much habitat.
(If either of them find an AK of the 47 subspecies they should probably let Mr Plod know fairly smartly.)
Martin