Migrating honeyeaters

Hi all,
For the last few weeks I have been watching flocks of honeyeaters, mainly
Yellow-faced as far as I can tell, moving past my place at Como, in southern
Sydney (34degree 59 S, 151 degrees, 04 E).
Interested to see that every one of them so far, without exception, have
been moving pretty much due South. I realise that there could be some
irregularity in the directions travelled as they follow topography, etc.,
but it still seems strange.
Any ideas anyone?
Paul