For European cultures, ravens, also called rooks, were a bad omen, an omen of death or of a sinister thing that is about to happen to someone. For Native American cultures though, the raven is a symbol of knowledge and intelligence.
Because the symbol I was already in common use to represent the amount of current in a circuit. You may ask then why was the symbol I chosen to represent current? Well because the symbol C had already been adopted to represent Capacitance! Go figure!