Oooh scary. My dog once found what he thought was a dead magpie in the woods. When he picked it up it went all squawky and flappy, at which point he nearly poo'd his proverbial pants and dropped it and did a runner.
Magpies family were not happy though, they followed us home swooping at us (about a 10 minute walk) and then sat on my roof for an hour making that machine gun noise!
I was a bit scared!