Those otters are nasty big weasels! Not always playing and sliding down banks on their bellies enjoying themselves. I almost stepped on one this winter who had just taken a gull that had come to close to his winter lair under a dock here on the estuary. He was swimming with this bloody mess and I don't know who got scared more when my foot came over the top of him when I stepped into the skiff.
I think you heard about the ADFG study where some high percentage (really high! - but can't recall numbers) of their transimitters from steelhead they had tagged ended up 3 or 4 otters dens! One of them floated by me a few weeks ago while I was fishing just hissing at me. Sheesh! Everyone does that this year!
I suspect those eleven Mallard ducklings wont fare very long with a big weasel there. And the wood duck family may have an lethal neighbor to contend with if he decides that pond is a good place to dine and stays around.