In Iceland when Ravens gather together it is caller a Raven Congress (Hrafnaþing). I have one in my garden on a regular basis. I feed the birds during winter. Not with corn but with leftovers from our kitchen. I put everything out, meat, fish, stale or moldy bread, rotten fruit, basically everything that would be tossed away as rubbish. The birds become by recycling plant and the Ravens love it when I put a leg of lamb or a rack of lamb outside. It is a good way to study their hierarchy and humour