This is a trumpeter swan (that is banded, haven't heard back on the origin of the neck band yet). The bird is preening (think of it as brushing its feathers). It's rubbing its head over its preen gland on the back of its body and rubbing the oil from the gland all over the rest of its feathers to keep them waterproof.
Although, between the pooping and the crazy head rubbing, it looks kinda drunk. Needs some wacky music in the background.