These two Great Egrets were standing on opposite rails of a pier in Shoreline Lake, Mountain View, and when I got myself at the right angle to them, the positions they took made it look like they were engaged in a stately dance. But this was out of mating season, and in any case, the known behavior of birds of this species does not include any such dance. My best guess is that they were simply independently surveying the water below them for possible prey.