Could this be a hen harrier?

Have spotted a male hen harrier the last few months. This was in garden yesterday for about 30 minutes. The images are rubbish quality, only had phone camera and did not want to open window as would have frightened bird away. It seemed to be trying to attack some smaller birds in a hedge nearby, and then just sat on fence post for about half an hour. 

Could this be a female hen-harrier?