Cooper's Hawk

Well, my observations don't seem to line up perfectly to the summaries on the reference page but I suppose there are exceptions to all rules. Last weekend I noticed 2 hawks coming and going from a nest high up on a pine. One spent some time in the nest seemingly building and arranging twigs and had immature plumage (in chest) as seen through binoculars. The other bringing in twigs was a mature colored Cooper's Hawk. I went back today to see if I had better luck with pictures. Today I saw at least 2 mature looking ones in the area of the nest but never in the nest tree. They spent most of the time flying from tree to tree in the area making the "near nest" call and attacking black and turkey vultures that were soaring by. I managed these pictures of one.