bird black Corvus corax raven beak blue Corvidae Corvus frugilegus crow England english feathers Great Britain nature perch Rook scavenger wings beach birds Corvus Crows heaven jackdaw monedula ocean ravens sand sea standing sunny water eye foot grey gutter head roof sit Sussex tile watch Australian raven blue black carrion eaters corvids corvus coronoides garbage collectors loud mournful omnivorous predators scavengers shiny black bare bare branches branches lone perched perching tree Australian-raven bearded bill blue-black carrion-eaters corvus-coronoides foraging garbage-collectors grass sharp-eyed shiny-black strong