Falcons fly again after ban on harmful pesticide

No longer endangered: A peregrine falcon with a pheasant that it has just killed. Their population in Yukon River has grown after the ban on the pesticide DDT. Photo: TNS

Half a century ago, when DDT was widely used in much of the United States, conventional wisdom held that peregrine falcons nesting in the cliffs of Alaska’s upper Yukon River were too far away from where the pesticide was used to be harmed by it.

That turned out to be wrong. But as recently published long-term research found, the falcons have made a remarkable recovery that began soon after the pesticide was banned.