What kind of hawk?

Emily Furnival

Hi! I was leading my elementary school class in GGP today (by Lloyd Lake) when a large hawk landed on the hill a few feet away from a gardner. He had a dark grey face and exceptionally puffy leg feathers (on of my kids said "I like your pants Mr. Hawk"). He's probably a common hawk, but I'd love to know what type! 

Thanks all! Sorry to ask such a simple question. 

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