How can you stop a very aggressive bird in my backyard from attacking my 2 dogs?

Two backyards away from mine, there used to be a nest in one of the trees. We noticed this bird nose diving our dogs for over a month now and called the conservation office to inquire. They told us that as soon as the fledgings were able to fly and take care of themselves, the bird would stop its aggressive behavior. Yesterday we saw it attack yet another crow and this time it repeatedly attacked it on a fence in front of my house, no where near the nest. We're not sure if the crow was fatally wounded or not. This bird is no bigger than a blue jay, but all gray except for white markings at the edge of the wings almost scalloped-like. He has actually pecked at my black lab's tail and made contact. And he has done the same thing with the smaller dogs in the neighborhood. He has attacked squirrels and the list keeps going on. We now have to sit with a water hose when we're in the backyard to prevent him from attacking our 2 rather large dogs. Concrete suggestions welcome.