I went back later (11:00 am) with binocculars and my camera which has a telephoto lens. There are about 20 of them floating; they are the size of one's hand held loose, palm down, not made into a fist.
Here is a shot taken further away. There were more of them on the south side of the loch but the shapes were little triangles, all the same.
I am guessing they are dead ducks as they are bigger than coots and smaller than geese.
I'd say there were 30 or so counting the little triangular shapes in the water. Why so many dead birds? It's a mystery! Later ... it's vegetation!
The other birds, including these mallards, were paddling about unconcerned and they were also feeding, i.e. tails up with heads in the water.