Why though? There are dozens of crows in my neighborhood. If I befriend crows will they come to expect food from me? What about the pigeons and seagulls? Will they come to resent me?
My policy on neighborhood birds has always been neutrality.
You can eventually train crows to bring you stuff. I’ve read stories of crows being trained to deliver money or cigarettes. My favorite was a guy who used to hang out with crows on his balcony when he smoked, and he had to move when he quit smoking because the crows would just bring him packs of cigarettes.
My policy on neighborhood birds has always been neutrality.