Konrad Lorez, one of the founders of the field of animal behavior and a Nobel laurete, did a lot of his research on jackdaws, which are a close relative of the crow. His book King Solomon's Ring is a really enjoyable read into his insights about their intelligence and social life.
For anyone interested in psychology in general, his text "On Aggression" is an amazingly well developed read on the habits of aggression starting with fish, then birds, then eventually mammals (concluding of course with humans).
The final explanation of why a loving father of four can firebomb a city filled with innocent people blew my mind as a younger man and shaped my worldview.
I think I'll add King Solomon's Ring to my amazon cart now.
