When not calling them "corbies", I usually call them "croworrookorjackdaw", all one word. I have so often pored over the bird book to commit the differences between them into my brain, but it just doesn't stick. It was a nice relief to be in north-east Scotland last year and see the "hoodies" - the hooded crows - and at least be able to identify them. Though all the millions of versions of gull and the guillemotsorrazorbills we saw there totally undid any certainty I had with bird identification.