The Fish and Wildlife Service has announced results showing the largest population of breeding bald eagles in the U.S. since World War II. Bald eagles in the lower 48 states have climbed from an all-time low of 417 nesting pairs in 1963 to an estimated new high of 9,789 breeding pairs today.

This updated estimate is based on information gathered by the states in 2004 or later. Minnesota tops the list with 1,312 pairs of eagles, followed by Florida with 1,133 pairs and Wisconsin’s 1,065 pairs. There are also eagles now breeding in the District of Columbia and the state of Vermont, which was the only state in the contiguous U.S. which lacked eagles until the first eaglets hatched successfully in 2006.

The bald eagle, which is protected as a threatened species under the Endangered Species Act, once sounded an environmental alarm for the American public when it was learned the widespread use of the pesticide DDT had the national symbol plummeting towards extinction.

For years after World War II, DDT (dichloro-diphenyl-trichloroethane) was used to control mosquitoes and agricultural pests. When it rained, DDT would wash off the soil and into the waterways. There, it was absorbed by aquatic plants and animals. Fish ate the plants and animals, and eagles ate the fish.

When ingested, the chemical compound would build up in the fatty tissues of female eagles and prevent the formulation of calcium necessary to produce strong eggshells. Consequently, eggshells thinned and cracked when an adult tried to incubate them. Widespread reproductive failure and a precipitous decline in numbers followed.

Rachel Carson, a biologist and writer for the U.S. Fish and Wildlife Service, became aware of the dangers of chemical pesticides including DDT, but was also aware of the controversy within the agricultural community which needed such pesticides to support crop production. Carson made the decision to produce her book, “Silent Spring,” after years of research across the United States and Europe.

When “Silent Spring” was published in 1962, Carson immediately became the focus of a storm of controversy. But as a result of her research and the publication of “Silent Spring,” the government eventually banned the use of DDT in 1972.

Today, Americans can see wild bald eagles in every state in the lower 48 and witness the living proof of Rachel Carson’s courage and determination. May 27 marks the 100th anniversary of her birth and provides a unique opportunity to honor this conservation hero at the same time the Fish and Wildlife Service is taking steps to celebrate the recovery of our national symbol and remove it from the federal list of threatened and endangered species.

The service proposed to remove the bald eagle from the list of threatened and endangered species under the Endangered Species Act. In order to ensure the eagle will be protected upon delisting, the service is working to finalize the definition of “disturb” and the bald eagle management guidelines under the Bald and Golden Eagle Protection Act.

Under terms of a settlement agreement, the service is to make a decision on delisting the bald eagle by June 29.

For more information on bald eagles in the United States, log onto www.fws.gov/migratorybirds/BaldEagle.htm.