White Tailed Hawks- twins

We hit the road for Tucson on 7 October 2007.
16 October 2007 - 10:10 AM.; RVP
2 White Tailed Hawks (mature); My first impression was of a Herring Gull; second impression was of an Osprey. Then the second (twin bird) was circling with the first bird. The bird was a large buteo. The black wing tips were too extensively black to be a gull. The tails had a thick black sub terminal band. The head and neck was massive. The birds flew toward the west. The birds were bright white on the ventral areas; mature gull white. EOB- 200 feet; OT- 4 minutes. I have seen a White Tailed Hawk with ornithologist Ray Little at Rockport, Texas.