Smart raven...

Depending on who I hear the tale from, this is a young raven or crow - the person who took the video says raven, which is fine with me.  In any case, it perched on their fence for about an hour squawking, until someone came out to investigate, to find that the poor thing had had a run-in with a porcupine and needed some help.  The rest you can see in the video.  Smart critters, corbies.