During World War II the US and UK armies used bodies of, respectively, over 54,000 and 250,000 what, as part of their communication and/or delivery systems?
Homing pigeons Pigeons were also used extensively in World War I; the shooting of a homing pigeon during World War I was an offence under the UK's Defence of the Realm Act. The US army's Signal Pigeon Corps was not disbanded until 1957, at which time it still maintained a corps of 1,000 pigeons which it sold or gave away. The Swiss army did not disband its Pigeon section until 1996.
During World War I and II the US army maintained a unit whose task was the training and use of what, for communication and reconnaissance purposes?