I can also recommend bulk roasted unsalted peanuts. They have some advantages: they're cheap, they don't crumble, so you can always have a few in your coat pocket, and they take some work from the crows. They'll enjoy the challenge, and you'll enjoy watching.
I once lived in territory of some ravens, and it was a deep pleasure to gradually become friends with one. It took maybe a year of consistent effort, but eventually he'd come hang out with me outdoors. I would say bits of Poe's "The Raven" to him, and when his turn came he'd respond with soft, friendly mutterings. He especially liked to visit when we'd grill and eat outdoors, as there was nothing he liked better than some some bone with bits of meat and gristle left on it.
Cashews are also great if you want to treat them. But we always bring kibble because most kibble is designed to be usable as a "sole" food covering a lot of nutritional needs at once. Extra points if you bring water and a flat bowl, they love to soften it up.
I once lived in territory of some ravens, and it was a deep pleasure to gradually become friends with one. It took maybe a year of consistent effort, but eventually he'd come hang out with me outdoors. I would say bits of Poe's "The Raven" to him, and when his turn came he'd respond with soft, friendly mutterings. He especially liked to visit when we'd grill and eat outdoors, as there was nothing he liked better than some some bone with bits of meat and gristle left on it.