This magnificent bird of prey flies over Grand Tetons National Park in Wyoming. The bald eagle is part of a conservation success story, for our national bird was once headed toward extinction. A rapid decline in bald eagle populations was one of the motivating factors in establishing the Endangered Species Act of 1973. The chemical pesticide DDT, previously thought to be safe, was causing high mortality rates for bald eagle chicks, as well as many other birds exposed to the chemical. DDT was banned, and the eagles’ numbers began to rise again.