In a Commentary piece on War on the Rocks it is argued that, 60+ years after the disbanding of the US Army pigeon service the military homing pigeon warrants re-examination. It provides a potted history of the use of pigeons by the US military – widespread use starting in WW1. It notes that both the French army and the Chinese army maintain small pigeon units, in case of communications disruption…
Incidentally, and not mentioned in the article, during WW2 not only did the British use pigeons for communications (one brought back news of successful landings on D-Day) and rescue (ditched aircrew released homing pigeons) – and there was a national pigeon service for pigeon fanciers to do their bit – but (incredibly) there was a Secret Pigeon Service that provided communications with SOE and Resistance in Occupied Europe and was even involved in “spying” (pigeons were dropped by parachute and if a local found it they could complete a questionnaire about German forces and facilities and pop it in the bird’s message container and send it home. It is claimed, I think, that such a method helped locate an important radar site that was subsequently targeted)…
https://warontherocks.com/2019/01/in-the-era-of-electronic-warfare-bring-back-pigeons/