Interesting group habits of Rooks. Sounds like JW's are "Rooked". Hmmm
We don't have Rooks nor Carion Crows here in the US. At least on the Pacific Coast. Carion Crows are a close relative of an Asian Crow, which is a close relative to the Hawaiian Crow, which is extremely endangered. Sad.
Your Carion Crow acts more like our larger Ravens in it's independent lifestyle. Here in Pac NW we have 2 races of crows - American Crow - spread across the US - looks alot like your Carion Crow, and the Pacific Crow, which is a little smaller and has a pointier beak and more irridescent plummage. I say races, because they will interbreed. Both usually hang out in small family groups, and are part of a larger extended group, or murder. The murder will get together whenever there is trouble, like a hawk or owl passing through, or in the spring and fall to reestablish their relationships and either mate, or prepare for winter. I've taught my family group to leave my cats alone!
I feed about 3 family groups now. Costco catfood is very good for them. In the 4 years I've been feeding, they have produced some very healthy offspring, one of which is now a family group leader. We have 5 regular fledglings feeding with us this year, and at least 4 others that have come by word of beak.
I'm learning to caw in several crow words. I know I've got it right when they respond. Amazing creatures.