Australian-raven beak bearded bill black blue-black carrion-eaters corvids corvus-coronoides crow foraging garbage-collectors grass loud mournful omnivorous predators raven ravens scavengers sharp-eyed shiny-black strong beach bird birds Corvus Crows heaven jackdaw monedula nature ocean sand sea standing sunny water Australian raven blue black carrion eaters corvus coronoides garbage collectors shiny black bare bare branches branches lone perched perching tree coast cornwall Lizard Point Corvus corax black and white blackbird graphic canada Corvidae curious driftwood feathers feet natural scavenger