What a good thing you remember to look up before letting the kids out. How scary. I know of only one way to get rid of hawks -- well two ways, one will land you in jail and the other is to remove the food sources.
We have a hawk that is living in our middle pasture near the barn. Either he is looking for mice the cats miss or perhaps he is hoping for a kitty snack.
I don't think he'll have any luck, there 'cause the kitties don't play fair.