The Coast Guard has added six pigeons to its San Francisco-based rescue squad, which searches for survivors of boating accidents. Tests show the pigeons have an 89 percent chance of success in detecting certain colored objects at sea, compared with a 40 percent rate for humans.
The Coast Guard puts a team of three birds into a pod mounted under a helicopter with the birds facing different directions so that each covers 120 degrees of a circle, officials said. If a pigeon sees orange, red or yellow objects, it pecks on a key that buzzes the pilot and lights up a control panel. The pilot checks to see which bird signaled and heads in the direction it was watching.
Biologist Jim Simmons, who developed the idea, said pigeons can take in a view as wide as 160 degrees, because their eyes, located on the sides of their heads, function independently and each eye has a visual field of 70 to 80 degrees. By comparison, a human eye has a visual field of only 2 1/2 degrees--that means, to see anything outside that field, a person has to move his eyes or turn his head.
The pigeons aren't much trouble, Simmons said. "All it takes to train them are little rewards of things like peas, barley and wheat."