Common Koel - range expansion to Victoria?

["Wendy" <>]

I find it particularly interesting that, while our northern (Qld, Sydney and
North, NSW) contributors are starting their annual 'Koel arrived' reports,
Birdline VICTORIA reported a Koel arriving in Ocean Grove (very S Victoria)
in the first week of May. Further reports of the bird 16 and 23 Sept.
I presume, barring human intervention, this bird has been resident somewhere
down south all year?
Or did it just do a very fast trip from up North all the way to Ocean Grove?
Before the SEQ and NSW lot turned up in those areas?
Wendy