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Kids
activites to celebrate bald eagle recovery
Introduction
All
living things, including humans, are connected to each other in
a “web of life.” When we remove anything in nature,
something else is affected. It has been estimated that a disappearing
plant can take with it up to 30 other species, including insects,
other plants, and higher animals. Endangered species are the fire
alarms telling us that the living things being affected include
us.
The bald eagle set off a fire alarm for the American public when
we learned why it had become endangered in the lower 48 states.
Because of the use of a dangerous pesticide called DDT, bald eagles
plummeted towards the brink of extinction.
For years after World War II, the government sprayed DDT (dichloro-diphenyl-trichloroethane)
to control mosquitos in coastal areas, and farmers used DDT to
control 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 then
eagles ate the fish.
When DDT broke down, the primary product, DDE, built up in the
fatty tissues of female eagles, preventing the formulation of
calcium release necessary to produce strong eggshells. Consequently,
eggshells were thin and cracked when an adult tried to incubate
the eggs. Widespread reproductive failure followed, causing the
eagle population to plunge.
During the 1940s, 1950s and 1960s, approximately 675,000 tons
of DDT were applied to U.S. soil. The peak year for use in the
United States was 1959 – nearly 80 million pounds were applied.
Responding to the eagle population decline nationwide, the Secretary
of the Interior listed the bald eagles south of the 40th parallel
as endangered on March 11, 1967 under the Endangered Species Preservation
Act of 1966. However, the decline continued.
Rachel Carson, biologist and writer, had long been aware of the
dangers of chemical pesticides but was also aware of the controversy
within the agricultural community which needed such pesticides
to support crop production. She had long hoped someone else would
publish an expose’ on DDT but realized finally that only
she had the background as well as the economic freedom to do it.
According to the New York Times, “one of the sparks that
caused Miss Carson to undertake the task of writing the book was
a letter she had received from old friends Stuart and Olga Hutchins.
It told of the destruction that aerial spraying has caused to
their two-acre private sanctuary at Powder Point, in Duxbury,
Mass.”
Rachel Carson made the decision to produce Silent Spring after
years of research across the United States and Europe. When excerpts
of Silent Spring were published in New Yorker magazine, Carson
became the focus of a storm of controversy and suffered from numerous
attacks on her professional integrity.
President Kennedy created a commission to review the government’s
pesticide policy and Carson was asked to testify before a Congressional
committee along with other witnesses. Not only did Congress subsequently
create the Environmental Protection Agency, but as a direct result
of the study, the Environmental Protection Agency banned the use
of DDT on December 31, 1972.
Then, the Endangered Species Act was passed in 1973, and the bald
eagle was listed as an endangered species in the lower 48 states,
with the exception of Minnesota, Wisconsin, Michigan, Oregon and
Washington, where it was listed as a threatened species. The Endangered
Species Act provided the springboard for the U.S. Fish and Wildlife
Service Endangered Species Program and its partners to work together
and help the eagle recover. Through captive breeding programs,
reintroduction of eagles into their historic habitat, protecting
nest sites during the breeding season, conserving roosting habitat
for food and shelter and enforcing the law against those people
who illegally killed eagles, the Endangered Species Act provided
significant protection for our nation’s symbol.
The publication of Silent Spring, combined with the habitat protections
afforded by the Endangered Species Act set the stage for bald
eagle populations to make a remarkable comeback.
But bald eagles weren’t the only endangered species impacted
by DDT. Peregrine falcons also teetered on the brink of extinction
due to the deleterious effects of DDE and eggshell thinning. Only
25 years after the government banned DDT, the peregrine falcon
recovered and was removed from the list of threatened and endangered
species.
In addition, the brown pelican, Guam broadbill, Guam Micronesian
kingfisher, Guam rail, Mariana crow, Northern Aplomado falcon,
Mariana gray swiflet, California condor, Wood stork and marbled
murrelet are all species negatively impacted by DDT/DDE in their
environment.
Besides DDT, a myriad of chemical compounds and pesticides can
affect endangered species. Endangered animals can ingest pesticides
via contaminated vegetation, seeds or prey. Aquatic species including
frogs and salamanders are particularly vulnerable to contaminants
as they live some or all of their life cycle in water, making
them susceptible to any changes in the environment. Aquatic organisms
can be exposed to pesticides entering the waterway from urban
runoff, but also through groundwater sources.
Herbicides are particularly detrimental to pollinators, lethal
to butterflies and dragonflies upon contact or its primary food
source. Similarly, an insecticide can indirectly harm an endangered
plant that may depend upon a specific insect pollinator.
For many species facing population decline from habitat loss and
degradation, competition with non-native species, disease and
historical over-hunting, environmental contaminants and pollution
in the environment could be the stressor that pushes them towards
extinction.
That’s why biologists with the U.S. Fish and Wildlife Service
Endangered Species Program continue to conserve imperiled wildlife
across the country. From manatees and panthers to mussels and
plants, the Endangered Species program builds on Carson’s
legacy by protecting the “web of life” that we are
all a part of. When one species goes, we are all affected.
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