It's a carryover from the English accent to say "drawring". The English mostly also say "sawr" instead of "saw". Example: "I sawr a large black raven yesterday, and at once sat down and sketched a drawring of it."

You can hear Al Stewart say "sawr" in a couple of lines in his songs, although his diction is normally impeccable. I always find it a bit disturbing to my North American ears when he does that.