The hunt continues

Okay, so these hawks are really hard to photograph. I chucked my point-and-shoot for a Nikon D700 with a 75-300mm 5.6 lens with the hopes that I might have better luck than Sunday. Owing to my keen vision, I spotted a beautiful specimen perched on a high fence abutting a fallow field about a quarter-of-a-mile away, near mile marker 5.4 on the Virginia side of the border.

I grabbed up my camera, and the bird didn't move a muscle. I opened the car door and carefully stepped out. She was perfect stillness on her perch. I began to walk, ever so slowly, down the road toward her. Utter and complete placidity. I started to lift my camera and she was on the wind. In the resulting distant and blurry photos, she resembles not so much a bird as a slightly-more-graceful-than-usual dust mote. I won't be sharing these ones - rather, I will be devising a new plan of action.

Any suggestions on how I should proceed?