Here is an article I found:
Tips for Scaring Off Returning Hawks at Bird Feeders, Page 2 of 2 - Associated Content - associatedcontent.com
It says to use a plastic owl??! I don't know if it works but it might be worth a shot.
I live in Arkansas. We have hawks too and I am very careful to watch for them and owls around Rosie. Some people say a hawk will not get a dog but an owl will for sure. They say the hawk will grab it but can't carry the weight. I really don't know and I really don't want to take any chances.
The best way to get rid of the hawk would be to call some of them Arkansas Rednecks! Ha ha. Problem will be solved.