Bogey bird at the Great Marsh

During last visit to MI while doing a patrol to the great marsh, we saw a large bird flying along the right side of the marsh. It settled high up in a tree maybe 300+ yards away (i.e., not the best for detail photos).
It looked like a hawk but seemed too wide/chunky. When the bird departed, it showed dark brown wing tops. My resulting image provides some additional specs, but not enough for me to identify using my books.
