Have a look.
Northern Harrier, Circus cyanea, male. Harriers can look quite owl-like when seen perched, as in this photo. They have exceptional hearing, and use this sense to track prey, probably to a much greater degree than most other hawks.
In flight, harriers are a snap to identify. They typically hunt low over meadows, rocking and tilting in a manner suggestive of a Turkey Vulture. Long pointed wings and a conspicuous white rump clinch the ID.
Cooper's Hawk data, also from the Columbus CBC and for the same years. Again, not an uncommon trend in many areas. While hawk predation may play a role in the decline of Columbus kestrels, I would say - based on over 30 years of participating in this count - that habitat loss is factor #1.
If you would like to learn more about kestrels and their status, check out this research from Hawk Watch International.