I initially identified this Accipiter as a Sharpie because of the rounded head, smallish bill, and the way the "cap" extends down the back of the neck.
The Massbird community responded to this and several people had convincing reasons why it's a Cooper's Hawk and not a Sharpie:
1. The hawk looks much bigger than the Mourning Dove. The average weights listed in the Sibley guide are actually very good arguments for Cooper's: Mourning Dove - 120g; Sharp-shinned Hawk - 140g; Cooper's Hawk - 450g.
Even taking into account a considerable size difference between male and female Sharp-shinned Hawks, a MODO shouldn't appear to be this much smaller than a Sharpie.
2. One of my main reasons for calling it a Sharpie was the rounded head. An angular head certainly is a good indication for Cooper's; but that doesn't necessarily mean that a rounded head indicates a Sharpie. As Marshall Iliff pointed out in an e-mail: Cooper's can really slick back their "hairdo". Naturally that will make the head appear more rounded and result in the "cap being pulled lower in the back".
3. The nape is roughly the same color as the cheeks and sharply contrasts with the "cap".
4. It has extensively pale lores.
5. Lacks dark semicircle just below the eye.
6. Has solid orange sides to the breast.
7. Has thick legs (not all that convincing an argument to me - I just don't see enough Accipiter legs to be able to judge that one).
Yet another field mark might be the white throat.
