Crows will chase off hawks, up to a point. I have abundant crows, and still have huge hawk issues. Crows will also snatch baby birds out of the nest, and killed 3 consecutive groups of fledging robins this summer. They also taught my chickens that fledging robins make great snacks. This is just one example of the horrors of the food chain in action. Do I kill the crows to give the robins a chance? Or do I leave the crows to help with the hawks????????