Mike,

Very cool!! While a Sharp-shinned Hawk would also fit the description and
would be more likely, a Merlin is very possible too. I have always found
Merlins more of a darker brown overall than a Sharpie. When seen up close
perching, Sharpies are also about pigeon size.

Other ID keys would be;
1. What took your attention when it flew - the length of the wings or the
length of the tail? When in powered flight, I always find the tail on a
falcon looks much less obvious than its wings. The opposite is true for an
accipiter.
2. Was there much of a difference in overall color between the back and the
breast? Merlins are usually more uniform front-to-back whereas Sharpies
tend to show more of a two-tone appearance.
3. When it flew, did it head for a wooded area, or into the open? Falcons
will tend to stay more in the open, using speed as an advantage, Sharpies
dip in and out of woods/fencerows, using cover as their advantage.

Dana