2014.5.16 a weird bird in Bulghang-cheon

There is a weird bird in Bulghang-cheon in Seoul.
Bulghang-cheon is a little stream of Han-river.

The bird was fluttering the wings continuously.
I have never seen that kind of a bird.
It is not a pigeon, sparrow, duck.
I wonder what is it doing.

Is it a monster or something?
Is it a drone?
Does it try to dry it's wet wings?
Is it sleep flying now?

I really wonder what species of the bird it is and what is it doing.