It's a Swainson's

 
  While scanning the closest stream of Broadwings yesterday at Pt. Mouillee, Jerry Stanley from Pennsylvania found a suspected Swainson's Hawk. As he described its location I had a strong feeling I had my camera pointed at the same bird. I only fired off a couple of shots of the high altitude bird as it soared among the Broadwings.  The photo didn't turn out well but I'm told that there is enough there to confirm it as a Swainson's.

Note the larger size of the lower bird

   A Swainson's wingspan is in the range of 46-54" while the Broad-winged's is only 32-39". 

   Below is the range of Swainson's from the Cornell Lab of Ornithology's website.

   Note that southeast Michigan lies outside this species normal range.  This explains that while the Detroit River Hawkwatch averaged close to 200,000 birds per year, they only average 6 Swainson's.