Hi,
As another example of the difficulty in telling the two apart (Cooper's and Sharpies), the recent TV saga on King 5 News over the last couple of nights involving a "Sharp-shinned Hawk" caught in a pigeon trap and another caught in a school is typical. All three featured birds were immature Cooper's Hawks, not sharpies. If you caught the error, you are doing pretty good.

Bud Anderson
Falcon Research Group
Box 248
Bow, WA 98232
(360) 757-1911
bud at frg.org