The crows in my area appear very healthy. I haven't seen any evidence of foot disease, but then I haven't been paying attention to crow's feet lately. I intend to start looking at their feet from now on. I haven't notice any aggressive behavior between American Crows. In fact quite the opposite. They congregate in big roosts and treat each other with kindness and respect. I call out to them when I pass/walk underneath them on the sidewalk. They are sitting on a high, and long extended telephone wire above me. They watch me and they answer back with their loud cawing. Sometimes over 50 birds cawing in unison. Sounds like a beautiful choir from God.
Yes, I have noticed foraging flocks of crows in my area, usually in the summer months. The crows sit in the
branches of one particular huge banyan tree. The flock numbers around 200 + crows. In the winter time
the crows relocate and sit on the heavy electrical wires close to the local Walmart Store. I haven't seen any other birds forming large flocks in my area.
The biggest and best surprise to me was that the researchers didn't use gloves in handling the baby or adult crows. Obviously it didn't affect the parent crows reaction to their babies after they had been handled.