None of these images are good, but do show the various field marks.

Most obvious on the flying bird was the bold, black 'M' across the upperwing. The dark secondary bar is also visible, and the bird lacks the white flash in the primaries of Bonaparte's. The size in comparison with Bonies is diminutive to say the least, and the foraging style is different as well. There were numerous 1st-winter Bonaparte's around today, and none even began to match the appearance of this bird.