Not sure on ID and only have these two rather terrible photos!
Think it could be a white cheeked honeyeater. Had to turn up exposure really high so a lot of lost detail. However I don't see any photos of white cheeked honeyeaters having a narrow white band. Most photos show white cheeked honeyeaters with a larger pie cut shaped white plumage.
It caught and ripped apart one of the racing pigeons from around the block and came back for more a day later
Poor thing is injured. So, I took it to USYD Vet hospital. Looks like a sparrow or a yellow faced honey eater, but the staff thinks it's some sort of fly catcher