I am posting this with much trepidation and emphasizing the word "possible" and after spending quite some time with various field guides trying to talk myself out of it.  

About 12:20 pm, today, Sunday, I was out on the deck (Bethesda, suburban D.C.) looking for migrants in the trees when I noticed a soaring bird overhead.  We have a lot of trees so I was not able to see it well at first until it moved into a small patch of open sky,  I immediately thought "this is something different."  The viewing conditions were not ideal, short time to look for identifying features and gray hazy sky.  It quickly became apparent that it was a buteo but had long narrow pointed wings.  I ruled out Red-tailed. Red-shouldered and Broad-winged quickly by shape and pattern (including no patagial marks or apparent "windows" in the wing) and Osprey and Mississippi Kite.  The bird did not linger, ceasing its circling and heading directly south (toward D.C., the Potomac, and northern Virginia).  Besides the long narrow wings, the bird had a banded tail with the rear band appearing wider, the flight feathers were dark and contrasted with the light feathers at the front, the body seemed light in color but the area at the head appeared dark.  I could not make out color or more detail in the pattern.  As I scoured the guides afterwards, I kept coming back to Swainson's Hawk which I have seen many times on visits to Colorado.

I don't feel that I had a good enough look (probably only a minute or two) and was not able to record enough details to say I am confident it was a Swainson's, but I want to pass this along in case anyone else sees this bird to the south.

Jim Nelson
Bethesda, MD