The ornithologist filmed the murmuration at dusk. In the first frame the flock was a tight column on the left, riding the updraft along the cliff face. By the second frame they had spread across the sky in a broad diagonal — from the upper left to the lower right, the way starlings do when the wind shifts. The third frame should have shown the full scatter. But a peregrine falcon struck the center of the diagonal, and the flock split: the two ends of the line held their positions while the middle three birds vanished, diving below the frame. The fourth frame showed the flock reassembled into a tight ball, their fear pulling them together.