blue cloud clouds colored colors coloured colours conditions contrast fine formations gray grey heavy light lighting movement perspectives shapes shining skies sky southern spreading sun textures variations various cloud formations weather white afterglow amber atmosphere atmospheric color colour contrasting dark darkening dusk evening glory golden lines mood setting-sun streaks sunset bright brilliant colorful colourful cross dramatic fiery flaming gold moody setting sun shadows silhouette silhouettes Australian breeding burrows control damage damaging danger destructive devastating digging ecosystem environmental erosion fauna feral invasive mammal mammalian pest pest pest control populated prolific rabbits reproductive spread threat uncontrollable widespread wild wildlife