In one episode of the NBC sitcom “Parks & Recreation,” Ron Swanson (the character played by Nick Offerman) brought down a delivery drone with a shotgun. People laughed, but Amazon apparently took the threat seriously. A recently publicized patent filing by Amazon shows that the company may program its aerodyne robots to detect and evade attackers. Further, the drones may be able to collect evidence so that they can report the incidents to local authorities.