How do you describe a flicker?

How do you describe a flicker, flicker can be described in different ways depending on whether you mean light flicker or bird flicker. For light flicker, you describe as quick, wavering, unsteady, fluttering light that goes bright then dim rapidly, on and off fast, like candle flame flickering in wind, with synonyms like twinkling, wavering, shimmering, fluttering, flashing, with light that is not steady but dances and wavers. For bird flicker, you describe as large brown woodpecker about 12 inches long, with black spotted belly, black crescent on chest, brown barred back, long pointed bill, and distinctive bright yellow or red underwings and tail that flash when flying, with white rump patch visible in flight, and loud call flicka flicka. Northern flicker described as ground feeding woodpecker that eats ants, with yellow shafted form in east with yellow underwings and red shafted form in west with red underwings. So how do you describe flicker, for light, describe as rapid wavering unsteady flashing light, for bird, describe as large brown spotted woodpecker with flash of yellow or red under wings when flying, with spotted plumage and loud call.