Lol I know, I've never had to deal with actual magpies but I've always had a weird obsession with birds, they're just like crows and crows will do the same thing. They know they're big, and they use it to their advantage. Hell, a small barn swallow still would have hurt! I don't blame you for being nervous. It's not breeding season right now? Here Spring's just beginning, so all the birds are going bonkers as they try and claim a mate. We've had bird after bird hit the window. Crazy little things. Definitely try popping it with the leash, and still try acting big, yelling when he comes after you, etc. If you make a big enough fuss, he might just go, "Well, I guess this spot is taken..." and move on.
"I am a being of transcendence. I have traveled across the universe, flying with the birds, swimming with the fish & dreaming with the dreamers. Once you realize this is just one plane, you'll be more than ready to discover the others."
"It's funny how I have one cat and get called 'crazy', but can have multiple fish without anyone saying a word."
*Floyd, Marley, Jagger, Dresden & Elvis.*