I believe it's the same bird observed at 5:23 on Monday morning, here. In the comments there, Quaestor and rehajm said owl. "Owl," "Yes, totally owl."
Jaq said: "I think that we are going to have to use Bayesian logic to figure out the bird, and before I zoomed in my first thought was buzzard, but after zooming in, I am betting my case of whiskey on owl," and then "Nah, I was thinking about it and I think that time of day, milieu, and the general silhouette has me changing my bet to a night heron flying home after working the night shift fishing," and then, "the tail is not right for a night heron."
Quaestor returned to say: "Night heron? Not enough beak or neck showing Furthermore, a night heron's legs trail behind the deck feathers in flight. I'm sticking with an owl, probably a great horned owl. They aren't usually associated with lake environments, but they are opportunistic hunters. This one could have spent the night hunting ducklings."
Rusty concurred: "Yeah. Goin' with owl. Good catch."