Nothing overly unusual about this, although I have not seen it before. Today I saw a Pied Currawong pulling apart something, on my shed (from my lounge window, about 3 metres away). I had enough time to get my binoculars. It was eating
a mouse. The whole head and front of the mouse was still intact, so was easy to identify but the middle was already pulled apart. Bits were carried up to the nest with chicks in my yard, before returning again. This is as noted in HANZAB that they always pull
apart larger prey, away from the nest and bring up pieces to the nest.
Philip