I have such good (?) photographs of this event, because much of it played out a few feet in front of us as we sat on a park bench in Sunset Bay, watching birds. We heard the squabble start a couple dozen feet off to our right as a woman walked near a gaggle of ducks.
The mob moved a dozen yards off to our left as it dawned on us what was going on. I'd told Anna that duck sex is sometimes more like gang rape than anything romantic. I've photographed brief snippets of that sort of action a couple of times previously.
We were talking about that when the mallard mob moved about 8 feet in front of our perch and continued as if no humans were around. These guys clearly have acclimated themselves to humans wandering through their lives, even taking pictures.
When the first few shots were blurry (In the descending dark of evening, I can see the camera's LCD pretty clearly, when I had a few seconds to reconnoiter my earlier results.) I upped the ISO to the figures past 1600, even added flash when I thought that might help. As shown in this shot.