A bird pal of mine, Al Wagar, who lives in the Seattle area, took this video of calling and courting black scoters, Melanitta nigra, that were on the coast near Edmonds, Washington. Black scoters are a large species of sea duck that dive for their dinner, eating mainly mollusks. They breed on ponds in northern boreal forests and spend the rest of their lives on oceans and salt water bays. Black scoter numbers show a long-term decline, possibly due to loss of boreal forest and coastal oil spills [0:43].
One of the cuter names I've run across for a group of ducks is "a paddling of ducks."