Hawk?

Description:

This bird was very large because it was far away and it still looked big based on the tree sizes I was thinking this was a Hawk or vulture. There was only one of them and the flight pattern was not circular so much as big swoops and loose figure 8's, but it was more gliding than flapping wings, then it would disappear over the trees and emerge far enough for me to turn myself 30 degrees or more.

Notes:

Unfortunately my lens was as far zoom as it would go. The sun was to my back, but all I saw was silhouette.