In 1940, the American psychologist B. F. Skinner was on a train when he saw a flock of birds flying in formation alongside it. He found himself thinking: what if birds could guide a missile?

Skinner was already famous for training animals using rewards. Pigeons, he knew, have excellent eyesight and can learn to peck at specific images with remarkable precision.

So he built a missile guided by pigeons.

How it worked

The idea was this. In the nose of a glide bomb, a lens would project an image of the ground ahead onto a small screen. A pigeon, trained to recognise the target — a ship, for instance — would peck at its image. If the target drifted off-centre, the pecks would move with it, and the movement of the screen would steer the bomb back toward the target.

To be safe, Skinner's design used three pigeons, each with its own screen. The missile would follow the majority vote.

It worked

Remarkably, the pigeons were very good at it. In tests, they pecked consistently and accurately, even under noise, vibration and changing conditions. In 1943, the project received funding.

But military officials struggled to get past the absurdity of it. In 1944, the project was cancelled; resources went to other guidance systems.