Well, is it really a duck. I thought ducks had a flat bill. Sort of the reason they are described as "duckbill." It looks like a cormorant to me. Is a cormorant a duck?
I am no ornithologist, but the only species of Cormorant in China is reported to be the Great Cormorant. The avilable informatino on Great Cormorant does not answer your question specifically. However, I propsoe that we can figure it out from some simple Q&A:
Does a Great Cormroant quack like a duck? No
Does a Great Cormorant look like a duck? No
So, is a Great Cormorant a duck? No way!