The following website has different articles and photos about birds, particularly pigeons and birds of prey, as spies in war: Spy birds
There is some very good info as you scroll down the website, such as the following (although I hate the idea of animals dying in a man-made war):
Brits’ pigeons of mass destruction revealed
ABC News, Saturday, May 22, 2004
One British airman thought pigeons could be used
to deliver biological weapons.
British intelligence agents secretly discussed plans to attack the Soviet Union with pigeons armed with biological weapons, documents made public by the National Archives reveal.
The bizarre Cold War scheme was hatched by Wing Commander WDL Rayner, a Royal Air Force officer who, in the aftermath of World War II, saw suicide pigeons as the future of warfare.
He was part of a top-secret “pigeon committee” set up after the war amid concerns that lessons learned from using pigeons to carry messages through Nazi German lines would be lost as the British military disbanded its flocks. Rayner’s idea called for pigeon lofts to be situated around Britain at locations with the same electro-magnetic and coriolis values as potential Soviet targets.
If war broke out, the birds – whose homing instincts depend on such values – would be released, each carrying a 55-gram capsule loaded with a “bacteriological warfare agent” such as anthrax.
“A thousand pigeons each with a two-ounce explosive capsule landed at intervals on a specific target might be a seriously inconvenient surprise,” Rayner wrote in a paper to the committee.
But the idea ran into turbulence from Britain’s domestic intelligence agency MI5, which branded Rayner “a menace in pigeon affairs” and disputed his participation on the committee.
In the end, Rayner’s plans for a full-scale experimental pigeon loft, with about 400 birds, never got off the ground, due to wrangling between the intelligence services and armed forces over who should pay for it.
The National Archives in London regularly releases intelligence documents no longer deemed to be top secret. Most are from World War II but some cover the pre- and post-war period.