Source Columba
According to a 2007 newspaper report, Source Columba (Latin columba, "pigeon") was the code name for the Confidential Pigeon Service, an unconventional British intelligence gathering operation in World War II. It involved air-dropping homing pigeons behind enemy lines in German-occupied France and the Netherlands as a means for locals to convey information, such as troop movements, to British intelligence. From 1940 onwards, more than 16,000 pigeon cases were parachuted into Europe, each case including – apart from the pigeon – sheets of very thin paper, a special pencil and a tube for storing the message, as well as French and Dutch instructions on how to fill in a report.