It is a merganser and looks like a small, white diving duck with a crested head.

Irene went down into the water as cleanly and smoothly as if she had been a diving duck.

Dexter the Diving Duck had come through and saved the day.

Diving ducks frequent the larger, deeper lakes and rivers, and coastal bays and inlets.

Do you mean to say you've never seen Luna Park, or Dreamland, or Steeplechase, or the diving ducks?

And I hear the English are making ships that will dive the same as diving ducks under the water.

We provide evidence of nuclear sequences homologous to the mtDNA control region in seven species of diving ducks (tribe Aythyini).