Susan, we carry "The Claremont Field Guide to the Birds of Australia" by Simpson & Day. Thankfully, the book is not as big as it's title, but it is good to use! ISBN 0 7343 0285 1, published by Penguin.
Thanks very much for that, Peter, I'll get down to the bookstore & buy that one. We've recently returned from a trip through Outback Queensland and were amazed by the variety of birdlife there (and also by how few types of birds we can actually name!)