That dark spot on the side is a foot stuck up under his wing. Apparently swans do that! I've seen up to six swans, at times, though there was only this one yesterday and none today.
And a bunch of these:
Took me some searching to figure out what they are. They're American Coots. This picture only shows a little, but they have GIANT FEET. Very cute. I hope they stick around and have babies, because they have the the world's ugliest chicks. *squee*