I don't think I have every seen this behaviour before. I have seen Swans bathing, and have posted them on here. I think we have all seen Swans, heads down under water, tails pointing high up into the air as they reach down to feed on the bottom of lakes or rivers. This is different though, this and several other Swans were actively washing and preening. Then they pushed their heads hard down into the water, and must have paddled very strongly and forced their entire bodies down completely under the water, looking like long white submarines. Although this shot does not show it, at times the water was totally covering the bird.
