A puzzle…. What was that all about?

Early this evening I visited the lake at the Taylor Dam. The lake was extremely well populated with Black Swans of all different sizes and development. There appears to be a hierarchy in Black Swandom that I have not observed before. Suddenly there was a thrashing of lake water when a very large swan, with black and white tail feathers all puffed up, took off in pursuit of another large swan. Was this Swan Courtship or merely territorial? What ever it was, the fleeing swan looked to be in for a rough time. I still don’t know if it was a display of Swan Rape or mere Thuggery.