I try to give people the benefit of a doubt about animal identification. But having worked as a wildlife rehabber it gets so...hard. I can't count on all my digits the calls we've gotten to come pick up an injured raptor only to find crows, a blue jays, a domestic parrot and...oh the horror of horror...a gull. We take gulls, but there is something fundamentally unsettling about being all suited up for combat only to have a beady eyed "Mine!" in response.
As for the birds of what ever sort they are, now is the time most birds are fledgling. It's possible you had more than one family group working together. Some hawks are so hopped up on parenting hormones they'll do that when normally they'd like nothing better than to eat each other. Time for an enclosed run or more dogs dedicated to guarding. How many did you end up losing?