While crows will eat the occasional baby bird, they eat only slightly more than white tailed deer do.
I see the American crow daily in my neighborhood and very often in our yard as we feed them peanuts.
We don't have Common Ravens in our area. I live in Alabama.
I think birds and other animals benefit from crows in at least a couple of ways. We have hawks in our area and the crows chase them away. They also yell loudly when there is a predictor around, such as a cat, which warns other birds and small animals.
I haven't seen anything in the lesson yet for me to know how to locate a crow's nest.