The Pigeon Bomb was the outcome of Project Orcon (Organic Control), also known as "Project Pigeon". Originally proposed by famous American behaviorist B. F. Skinner, the idea was adopted by the United States Navy during World War II before being canceled in October of 1944.
Missile guidance technology at the time was unreliable and subject to frequent jamming. It was also expensive an difficult to package inside a bomb casing. Eager to do his part in the war, Skinner proposed a solution to these problems: use trained pigeons to guide the missile to its target. Pigeons were ideal for this purpose: Pigeons are completely immune to jamming, pigeons are easy to obtain and inexpensive to keep, and pigeons are small as well as light.
To guide the rocket, three pigeons were placed inside the casing. The three pigeons were independently housed, the steering of the missile being handled through majority rule. A lens directed an image of the target to a screen in front of the pigeons coated with Tin Dioxide (SnO2), an electrically conducting material. The pigeons would peck at the target, their pecks causing changes in the electrical current flowing across the screen. The internal electronics of the missile would then convert this change in electrical current to directional instructions for the missile. If the pecks--and therefore the target--were near the center, the missile would maintain its path but if they were off center the pecks would correct for the errors and 'steer' the missile back to a correct line of flight. An advantage of this system is that not only do these pecks guide the missile but they also compensate for the imperfections in the manufacture of the missile preventing it from flying completely straight.
Revived in 1948, Project Orcon was pushed even further. In simulated tests, approximately 55% bombing runs were successfully navigated by pigeon bombs. The average pecking frequency was 4 pecks per second and about 80% of pecks landed within a quarter inch of the target on screen. However, the bomb only worked during daylight hours and had the maximum range of the optics used to project the image on the screens. Because of these limitations and others, the project was cancelled again in 1953 and relegated to military obscurity.