flock of rooks sits on fruit (nut) trees to look for walnuts

animal animals behaviour bird birds birdwatching blues branch city clever concept corbie corvus crow crowd depression doldrum dumb feather flock fog fruit gatherer gray heavy horde huddle intelligence migration migratory nut of ornithology park prey raven rook rooks scavenger sits sitting smart stressanxiety swarm synanthropic temperate tree trees walnuts waste wildlife wings winter zone