VANCOUVER Spurned by U.S. regulators, Amazon.com has turned to the one country where flying delivery robots are still welcome: Canada. On Monday, the U.K.s Guardian newspaper revealed that the online retail giant is testing its latest prototypes for package-carrying drones at a top-secret site in British Columbia. We are rapidly experimenting and iterating on Amazon Prime Air including outdoors at a rural test site in Canada, wrote Amazon spokesperson Kristen Kish in an email to the National Post.