Magpies Are Destroying My Garden! Any Solutions?

I'm at my wit's end with some pesky magpies that have completely wrecked my garden this year. They've torn the heads off every single flower, yanked out my strawberry plants and shredded them, and even turned my tiny pumpkins into casualties. They've ruined my gooseberries, raspberries, blackcurrants, and tomatoes by pecking holes in them without eating any of it. I've tried everything from covering my plants with bird netting to using organza bags, but they just rip through them. Lately, they've even started messing with my car—like pulling the sealant from the door. I've tried luring them away by feeding them at the far end of my garden, hanging CDs for a distraction, and even setting up a scarecrow. Nothing seems to work, and it's driving me to the brink. I'm even considering moving before next summer if I can't find a solution. Why are they doing this, and what can I do to stop them?