Raptor ID Required

Not a clue but it sure is a large one.

 

Hi Jim,

I am looking at my Sibley's book. A good ID is going to be difficult from the photo with the branch in the way. I think I see white on the cheek behind the branch, but it might be fuzz on the branch.
A Peregrine Falcon, the fastest critter in the world, is a logical choice. it matches the dive bombing of ducks that you described. However they are smaller (16 inches long) than your guess (do your eyes have a 1.5x multiplier or just your camera? :lol: ).
Your coastal Mass. location (assumed) is a spot where there are a lot of "rarely seens" due to blow-ins from Atlantic Storms.
The Gyrfalcon is one of those and it is bigger (22 inches long). Somewhat similar coloring, but not the white on the cheek. However it usually does not dive bomb, but mostly chases horizontally.
The only other logical possibility is the Northern Goshawk which is a regualr in your area. It is about the right size (21" long) and again hunts birds, but usually "in ambush" rather than a chase down.
Hope this helps. As you know Janet Zinn is probably the best ID person here, try to ask her by PM if she does not see this.

Bob

 

I first thought Merlin or Peregrine. I thought the Peregrine had some feathers coming down the legs? I don't see them here and 25 inches is pretty big. But the white on the cheek does resemble the Peregrine. Please post answer here or send pm if you get positive id.