CLOSED: Black or Mottled Ducks????

My books and online pictured do not quite match. But we have both here in North Florida. In the next small pond where a about 5 Mallards feeding

I typed this late last night.

Is these American Black ducks or are they Mottled ducks?

There was a small flock of Mallards near by but they did not match them

Mottled for me - look at the feathers on the flanks, they have arrowhead marks on, whereas on Black, they are plain dark brown.

Resin

thank you every much.