Over the summer my partner taught our local gang of crows that if they come to our house in the morning and the afternoon and make some noise, she'd come out and throw them peanuts and meal worms. We're not on petting them terms, but we've got an understanding. :D
There was a documentary in Japan a few years ago that showed local crows going absolutely crazy for mayonnaise. (Ketchup, on the other hand, they had zero interest in.)