The culprit shown has been in my backyard (or the neighbours) for the last 4 days or so. It has an annoying 'chirp chirp' that doesn't stop and is very loud which is why I noticed it.
I get the impression that it's a young bird but it can fly quite well.
I've trolled through a few online references but couldn't see it.
My apologies in advance for the poor shot - must be something wrong with my camera
With a bit of reasearch, it could actually be the female of the common koel. I've seen a local male, it's a largish bird, black, and its 3am "KOELLLL" cry has earnt it a price on its head.
So far, I think Mental is closest. It certainly looks like a juvenile koel except the colour seems off.
It looks a lot different to the wattle birds that I'm seeing in the backyard - I have a lilli pilli that's heavy with berries at the moment and the wattle birds gorge until they can hardly fly.
Eudynamys scolopacea aka Common Koel. The appearance matches the female but its behavior suggests it is a juvenile. If you keep an eye on it I suspect you will find that it is still being fed by the foster parents. They make a lot of noise when first out of the nest to make sure that aren't lost or forgotten. It seems a bit late in the season - it's been a few months since a male sat in the tree in the neighbour's yard and called all day and all night - but that is the only thing it could be.
The barred tail, the two different patterns on the wing, the light underside and the light streak from the eye towards the shoulder all match a koel better than a pheasant coucal. What was the size? A koel is 38-46cm long whereas a pheasant coucal is 60-80cm long.