The letter was the push Carson needed to investigate DDT

In 1958, Rachel Carson received a letter describing songbirds suddenly dropping from tree branches.The writer blamed their deaths on a pesticide called DDT that exterminators had sprayed on a nearby marsh.The letter was the push Carson needed to investigate DDT.She had already heard from scientists and conservationists who were worried that rampant use of the pesticide posed a threat to fish, birds,and possibly humans.