Well, not really a dance, but definitely some fancy footwork for scaring up food. I watched this pair of swans for almost an hour while they preened every single feather, fluffed them out with a few quick wing beats and then settled down to dredge up their dinner from the bottom of the lake.
Feather fluffing action
Mud raking action with the feet; wings slightly lifted while the legs churn below.
Both birds are churning up the mud here, and then they simultaneously dunk their head and neck down, bottoms up while they scour the bottom with the bill.
They must have brought up something good to eat because their foraging activity attracted a pair of mallard ducks, who tried to snack on the left-overs.
It’s possible that preening and then fluffing those feathers with a good wing stretch helps them stay waterproof for the dunk feeding that follows.
You don’t really appreciate how big these birds are until you see the length of that outstretched wing.