I went to check my cams today and seen about 15 or so black ducks in the river. I wish I could have gotten closer to better discribe them but the entire bird looked black from my vantage point.
Don't Coots sorta "run" on the water first to get up speed to fly?
I know a Mallard can go right out of the water.
Sandusky Bay is the largest single breeding ground for them in North America.
Looking at those pics I would say Coots. Definitely BLACK.