The Lost Art of Reading Nature’s Signs by Tristan Gooley

“In the 1930s, executives at the Union Oil Company of California were aware that turkey vultures would gather at the site of any gas leaks in their pipes. They used this awareness as part of their detection strategy, but they weren’t exactly sure why the birds gathered at these spots. A coincidental conversation between those in the oil business and those in bird research led to the discovery that the gas that leaked from fractured pipes contained traces of the same chemical, ethanethiol, that the turkey vultures were used to sniffing for in their search for decomposing bodies. In a triumpth of lateral thinking, the executives at Union Oil decided to artificially boost the quantity of this chemical in the gas. This had the effect of enlisting the support of the vultures whenever a pipe leaked gas.”

-Tristan Gooley, 2014