The History of Bald Eagles
Much of the history of Bald Eagles in America before European settlers arrived
is lost. Native peoples understood a great deal about eagle numbers and where
they were found, and eagles have always been important figures in Native
American culture. But sadly, much of the early history was lost when, for
over a generation, native children were prohibited by the government from
learning their native languages in school and often separated from the elders
who kept oral traditions alive. So most of what we know about eagles is limited
to discoveries after European settlement.
Sure enough, a century after Audubon wrote those prophetic words, eagles were, indeed, gone from most of their early haunts. What had happened to them? A whole variety of things:
Scrambled Eggs Instead of Babies
By the end of the 1800s, eagle numbers had dropped dramatically. In the 1930s, people became so concerned that they drafted the Bald Eagle Act, which was passed in 1940. Unfortunately, at the same time, people started using a "miracle pesticide" called DDT to kill mosquitoes. (See the Journey North lesson about DDT) Although DDT probably contributed to the deaths of some eagles, its worst effect on them was to prevent them from reproducing. And the majority of eggs that eagles managed to lay during the late 40s, 50s, and 60s had shells so thin and fragile that the eggs got squashed when the mother eagles tried to incubate them. One of the most frightening things for ornithologists was realizing that as low as eagle counts were, virtually all of the birds sighted were adults. It takes eagles 4 - 6 years to assume their adult plumage, and that meant that for more than 6 years, virtually no baby eagles had been born.
Trying to Help
Bald Eagles are the national emblem of the United States, so naturally Americans wanted to help them. The United States officially declared the Bald Eagle an endangered species in 1967 in all areas of the United States south of the 40th parallel. The Endangered Species Act was passed in 1973, and on July 4, 1976, the US Fish and Wildlife Service officially listed the bald eagle as an endangered species over the entire nation (though it was considered "threatened," not "endangered," in Alaska). Strict enforcement and heavy fines prevented most (but sadly not all) eagle shooting.
Meanwhile, ornithologists were piecing together information about DDT and how it was affecting birds. In 1962, Rachel Carson published a book called Silent Spring, warning people that if we didn't use pesticides more wisely, we'd destroy bird populations and ultimately ourselves, too. Public pressure led to several states banning use of DDT by 1968. In 1972, the new Environmental Protection Agency banned virtually all use of DDT in the United States.
all this work, eagle numbers started to recover. By the early 1980s,
eagles were being seen regularly in more and more places, and immatures
were being found once again. DDT remained in eagle tissues, and in
the environment, but little by little it was decreasing. And little
by little eagle numbers increased. And then faster and faster. First
the eagle was removed from the endangered list in Minnesota, Wisconsin,
Michigan, Washington and Oregon (it was never considered endangered
in Alaska). Then in July, 1995, the US Fish and Wildlife Service upgraded
the status of bald eagles in the lower 48 states to threatened.
In February, 2006, the U.S. Fish and Wildlife Service announced action that could lead to the Bald eagle coming off the endangered species list within the next year or so. Fish and Wildlife experts say this change in status won't change the way eagles are managed and protected. Bald eagles and their habitat will continue to be protected.
Try This! Rooting out the Problem
Go back to the list of things that happened to reduce eagle numbers. Which of them are still happening today? Which have stopped happening and why? Based on your answers, which do you think were CRITICAL for eagle populations, and which were not? To learn more, see our lesson on Eagle Populations.