I have heard, and seen photos, of birds that have feathers that are not normal colours, not normal for the species that is. This is the first time I have seen them for myself.
To me this looks like a Crow with white wing feathers.
As usual you can click on the image to view it larger and also see some others of the same bird on flickr.
I spotted this bird on the other side of the river from Denso Marston Nature Reserve on 14th April 2012.