According to a book I read, Cheyennes divide birds into three groups: plain, great, and sacred. To my great amusement they count magpies into the sacred ones. They like them because they live close to humans, talk, and announce visitors.
If crows are social and they have their own theory of mind it’s not a huge leap to suspect they’d make friends or try and give friends what they think are valuable gifts and that wouldn’t need to be limited to just other crows.
I think this is well established.