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THE BALD EAGLE: MAKING A COMEBACK
THE BALD EAGLE:
MAKING A COMEBACK
The American bald
eagle—the symbol of the United States and an emblem of strength—was a
common sight throughout colonial North America. More recently, however,
the bald eagle fell on hard times. Its numbers dropped precipitously—to
fewer than 5,000 nationwide in 1979—until it was in danger of
extinction. Several factors contributed to its decline. As European
settlers pushed across North America, they cleared many thousands of
square kilometers of forest near lakes and rivers, thus destroying the
bald eagle's habitat. Eagles were hunted for sport and because it was
thought they preyed on livestock and commercially important fish. In
fact, bounties were offered for dead bald eagles as recently as 1952. In
addition, eagles' numbers dwindled because they could not reproduce at
high enough levels to ensure their population growth or their survival.
This reproductive failure was the direct result of the eagles ingesting
prey contaminated with the pesticide dichlorodiphenyltrichloroethane
(DDT). DOT caused the eagles' eggs to be so thin-shelled that they
cracked open before the embryos could mature and hatch. Mercury, lead,
and selenium were other environmental pollutants that harmed bald
eagles. More recently, the 1989 Exxon oil spill in Prince
William Sound caused the demise of many Alaskan ha Id eagles.
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Conservation efforts have helped the
bald eagle make a remarkable comeback. In the mid-1970s, the first
eagles to be bred in captivity were released in the wild. In
addition to raising birds in captive breeding programs, biologists
also remove eagle eggs from their nest-, in the wild, raise the baby
eagles in wildlife returns and return them to the wild. (Removal of
eggs actually helps increase the number of eagles, because nesting
eagles commonly lay more eggs to replace those that were removed.)
As a result of continuing efforts, the number of nesting pairs in
the continental United States doubled from 1,000 to 2,000 between
1975 and 1990. |
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Today many states are reintroducing bald
eagles to the wild. Save The Eagle Project (STEP), a private, nonprofit
conservation organization, works with the National Fish and Wildlife
Foundation to restore bald eagle populations in the United States.
Federal and state governments have supported such efforts, and private
and corporate donors have also been generous in their support.
Although bald eagles are still low in
number in every state but five (Washington, Oregon, Minnesota,
Wisconsin, and Michigan), it is clear that they have a fighting chance
for survival. Studies are being conducted to determine the precise
habitat requirements for these birds so that, once their numbers have
been restored, they can be sustained.
The world is a richer place because of the
bald eagle. Today it symbolizes more than a country, for the bald eagle
demonstrates that our biological heritage can be preserved if enough
people care to do something about it. In this chapter we examine the
importance of all forms of plant and animal wildlife and consider
extinction, which has become an increasing threat to so many species.
Finally, we explore what can be done to preserve our wildlife
resources and save the many endangered species from disappearing from
the Earth forever.
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