Early in World War I, parrots were placed in the Eiffel Tower to detect the approach of aircraft, which they could hear 20 minutes before they became audible to human ears. Unfortunately, they proved unable to distinguish between German and French planes.

The British navy also briefly tried to train seagulls to perch on enemy periscopes, in hopes they might defecate opportunely and blind the Germans. “For a short while,” writes historian Colin Simpson, “a remote corner of Poole harbor in Dorset was littered with dummy periscopes and hopefully incontinent sea gulls.” Churchill canceled the program.