Once I was picked on by crows in my neighborhood. A few birds would swoop down and tried to / made a show of pecking me on the head. I picked up fallen twigs about the size of walking sticks which I swung above my head like a helicopter's rotors. Did that a few times and the birds stopped bothering me.

The attacks started after I walked past a crow on the ground that was apparently injured or something. Once I _made eye contact_ (!) with that crow, the others up in the tree went beserk and started the attacks.