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Endangered Species Act (GMHDRNC)

TopicHabitat and Management - Population Surveys
Habitat and Management - Species and Habitat Management
Laboratory and Hands-on Activities - Food Chain / Web of Life
Wildlife - General
Learn about the history of the Endangered Species Act through the stories of three North American animals: the American alligator, the bald eagle and the peregrine falcon.
Grade LevelK - 12
Recommended SettingIndoor or outdoor classroom
LocationGovernor Mike Huckabee Delta Rivers Nature Center, Pine Bluff
Education Program Coordinator, 870-534-0011
Duration45 minutes - 1 hour
Suggested Number of Participants10 - 30
  • Learn about the Endangered Species Act.
  • Understand the need for game regulations and agencies.
  • Learn about the decline and restoration of alligator, eagle and falcon populations.
  • Evaluate how human populations impact wildlife.
Key Terms*

DDT (dichlorodiphenyltrichloroethane)


Endangered Species Act


Live animal: alligator or peregrine falcon



Successful legislation such as the Endangered Species Act (ESA) and the events that led to it point out that wildlife-human interaction must be managed. The 1973 ESA (administered by the U.S. Fish and Wildlife Service) was passed to slow the decline of native species. Animals identified as “endangered” are those close to extinction throughout most of their native ranges, while those listed as “threatened” are simply likely to become endangered. The American alligator, bald eagle and peregrine falcon are success stories of the ESA but sharply contrast with those animals whose fate could not be turned, such as the rapidly disappearing Florida panther.

  1. These stories can be told in any order, but relate the natural histories of the alligator, bald eagle and peregrine falcon.
    • American alligator – The American alligator is North America’s largest reptile, growing up to 18 feet. When settlers to the southeastern United States forced other big predators from their home ranges, the alligator hung on in the millions in the heartland of the south. However, when their skins became fashionable after World War I, populations plummeted. During the 1920s, about 200,000 alligators were harvested yearly for their hides. By 1943, Louisiana alone lost more than 90 percent of its alligators. Finally in 1967, the government declared the alligator an endangered species and granted full protection. State and local agents created monitoring projects and restocked native locations with juveniles hatched in captivity. Within twenty years, the U.S. Fish and Wildlife Service pronounced it fully recovered. However, because the animal is similar to the extremely endangered American crocodile, they are still listed as threatened. The recovery was so successful in Arkansas that the state began to offer a few alligator hunting tags in 2007.
    • Bald eagle – Selected as our national symbol in 1782, the bald eagle was nearly lost due to habitat destruction and degradation, illegal hunting and contamination of its food source. As early as 1940, laws were passed to end hunting of the disappearing bird. Despite the laws, only 417 nesting pairs remained in 1963. For those that remained, raising a clutch of eggs was more difficult with the accidental introduction of DDT to the eagles’ diet through contaminated fish. DDT was used to control mosquitoes and the runoff ended up in the water supplies from which eagles drew most of their food. DDT weakened the eggshells, often causing death before the birds hatched. In 1962, Rachel Carson’s book “Silent Spring” exposed the nature of the pesticide, and within a decade, the harmful chemical was banned. By 1967, however, the eagles were endangered, spurring further law enforcement, breeding programs, nest site protection and reintroduction. In 1995, eagle populations were listed as only threatened, and finally, in June 2007, the bald eagle was removed from the list of endangered or threatened species. 
    • Peregrine falcon – A peregrine falcon can reach speeds of nearly 200 miles per hour in a dive, but not even a swift getaway would save the species from near extinction in the mid-1900s. Much like the bald eagles, DDT weakened their eggshells. Unlike the eagles, however, peregrines were receiving the pesticide from their primary prey, songbirds, which ingested DDT-riddled insects. Peregrine falcon populations were never large, but of the three sub-species on the North American continent, only one escaped endangered or threatened status because it lived where DDT was used less. By the 1960s, the falcons had all but disappeared in the eastern United States, and populations dwindled by 80 to 90 percent in the west. In 1970, the bird was listed as endangered and the USFWS, state agencies and private organizations such as The Peregrine Fund restored falcon populations through captive production of young and reintroduction. By 1994, the peregrine falcon was removed from the endangered list.
  2. Present the animals and point out some features on the American alligator or peregrine falcon.
  3. Answer any questions.
  • How can we learn from the conservation histories of these animals?
  • What chemical affected the bald eagle and peregrine falcon? What were its original purpose and its accidental effect on wildlife?
  • When was the ESA?

DDT (dichlorodiphenyltrichloroethane) – introduced during the 1940s, DDT killed insects that spread disease and fed on crops. (Swiss scientist Paul Müller was awarded the 1948 Nobel Prize in Medicine for discovering DDT’s insecticidal properties.) DDT is toxic to many animals, including humans, not easily degraded into nonpoisonous substances and can remain in the food chain for prolonged periods.


Endangered (species) – an organism at risk of extinction throughout all or most of its range


Endangered Species Act (ESA) – designed to protect critically imperiled species from extinction as a “consequence of economic growth untendered by adequate conservation"


Threatened – an organism or species in danger of becoming extinct