I came across the group of feathers in the first photos, I wasn't sure what they were. A couple of metres further I came across two wings (One of the wings is pictured in the fifth photo). A metre further on I, unfortunately, came across the leg, spine, and head of a male Gang-gang. Most of the flesh had been picked off. It was a fairly recent kill, as I had been to the same area the day before and it wasn't there.
I thought that a Wedge-tail Eagle may have been the culprit and asked Stuart Rae about this. Stuart said...|The feather in photo 1 has been plucked not bitten off so likely a raptor not a cat. Although if any other feathers were bitten off it was a cat. A wedgie would have eaten the wing bones not picked them clean. A goshawk would not crunch the bones from the spine. So it does look like a Little Eagle could be a very possible candidate. They can crunch small bones. They eat rosellas whole. Gang gangs are sitting targets at the moment as the birds, especially the males are sitting outside their holes. LEs snatch rosellas when they do that, and there are plenty of them doing the same thing just now. " So one threatened species may be sustenance for another one. Thanks for posting this interesting sighting.