When Crows Attack!

Spotted two crows attacking a Buzzard. They were quite high and far off so had to zoom in a fair bit so poor quality. It's very difficult to hold the camera steady enough when zoomed.
The Buzzard doesn't appear to have anything in it's beak so I don't know why the Crows are so persistent in their attack. Probably trying to chase it away, but from what? If it's their nest you'd think they were far enough away now to give the Buzzard a break!