Cooper's Hawks are the commonest of the three accipiters that we have recorded at Leaning Oaks, and sightings occur frequently.  We rather suspect that this species cruises the property several times a day.  Accipiters are bird specialists and I'm afraid that they have a rather different interpretation of what a "bird feeder" is for.  Predation attempts are frequent, and often the high drama of the day.  In late August of 2012 a family group of three young and two adults moved into the yard for almost a month.  Bird use of the property plummeted and we went from using four gallons of bird seed a week to less than one for the entire month.  When they finally moved on, bird numbers rebounded.

Separating Cooper's from Sharp-shinned Hawks can be difficult with some birds. A couple of websites that are very helpful are:

http://static.birds.cornell.edu/pfw/AboutBirdsandFeeding/accipiterIDtable.htm

https://www.carolinabirdclub.org/misc/id/accipiters.html