Unusual harrier behaviour

I saw something I have never seen before tonight. As I was coming away from Russadale quarry I had the dog running on a right good bit in front and was messing about in the heather just off the track. A hen harrier came over Chris's house down the field and over the heather. It made for the dog and circled around it five or six times. It really looked as if it was looking to nail anything the dog would have put in to the air. I might be assuming a lot here but it really looked like it was taking advantage of the dog buldering about.