In 1963, one year after Rachel Carson’s Silent Spring was published, bald eagle populations in the lower 48 U.S. states hit an all-time low. Officials counted just 417 nesting pairs—a shocking fraction of the estimated 100,000 birds that once soared the skies in the 18th century, and a grim reinforcement of Carson’s warning against agriculture’s indiscriminate use of chemicals like the pesticide DDT. Other species’ numbers were plummeting as well. A postwar boom in construction, logging and agriculture was polluting the nation’s air and water and degrading habitats for many animals, including grizzly bears, whooping cranes and shortnose sturgeon.
Amid a groundswell of public concern for the imperiled wildlife and the broader environment, the federal government began implementing a series of conservation measures. In 1970, Congress established the Environmental Protection Agency, which in 1972 outlawed most uses of DDT. Then, in 1973, President Nixon signed the Endangered Species Act, which mandated steps to protect and restore plants or animals identified as “threatened” or “endangered.” In doing so, it provided a framework
for protecting species and their ecosystems from further decline, and it signaled to the world that direct action could make a difference.
In the 50 years since the act was adopted, more than 1,000 fish, mammals, insects, birds, flowers and other species have been listed under the act, and more than 50 have rebounded because of its protections, including some that The Nature Conservancy has helped restore. One of them is the bald eagle, which was “delisted” in 2007 after the bird’s numbers recovered. Now the eagle can be spotted in nearly every state.
Who’s to say what the Endangered Species Act’s next 50 years will hold? The act will no doubt be tested more than ever before as the effects of climate change, coupled with a global biodiversity crisis, pose unprecedented threats to the creatures it was designed to protect.
In the birding world, a Kirtland’s warbler sighting is a big deal, and for good reason. The sparrow-size songbird has a very specific range and habitat: In the summer it nests on the ground only in young, dense jack pine forests in or adjacent to the state of Michigan. As the weather turns cold, the bird migrates to the Bahamas and nearby islands and nests in coastal scrub habitat. By the time the Endangered Species Act was signed in the 1970s, “there were less than 200 singing males,” says Patrick Doran, TNC’s associate state director in Michigan. The species faced two threats: the suppression of natural wildfires needed to maintain young tree growth, and predation by the brown-headed cowbird, which deposits its eggs in Kirtland’s warbler nests, creating a competitive environment in which the warbler chicks often lose. “They were getting hammered,” says Doran.
Through habitat management in the form of controlled burns and tree replanting, and through reducing the prevalence of brown-headed cowbirds, Kirtland’s warbler populations have risen dramatically. Delisted in 2019, current estimates suggest some 2,300 breeding pairs are alive today. Still, Doran says, the Kirtland’s warbler is reliant on continued conservation, and its fragility is perhaps what makes sightings so memorable.
Fender's Blue Butterfly
Icaricia icarioides fenderi
By 1937, biologists believed that this one-inch butterfly had gone extinct after losing much of its habitat in Oregon’s Willamette River Valley. “Nearly all native prairie [there] has been converted to agriculture, urban development and other land-cover types,” says TNC Willamette Basin Steward Jeff Rosier. In particular, the insect depends on Kincaid’s lupine, a wildflower upon which it lays its eggs. But in 1989, small populations of the butterfly were discovered, and in 2000 it was listed as endangered. Since then, numerous conservation efforts have allowed this tiny pollinator to rebound. Its range has doubled and known population sites have quadrupled, leading to its recent “downlisting” from endangered to threatened.
This three-inch minnow “really speaks to the heartland of the U.S.,” says Steve Herrington, a TNC freshwater restoration strategy manager. Found in streams and creeks of the Great Plains, the shiner was listed in 1998 as endangered after centuries of agriculture-related development destroyed its habitat. Though the fish is still listed, ongoing land and water restoration projects have helped. One experimental program breeds shiners in a creek on Dunn Ranch Prairie—a TNC-owned preserve—and reintroduces them in nearby waterways. The collaboration with the U.S. Fish and Wildlife Service and the Missouri Department of Conservation has been so effective that the state is now testing new stream-restoration techniques.
There are only two species of alligator in the world: American and Chinese. The former was listed as endangered under earlier legislation—the Endangered Species Preservation Act of 1966—after hunting pushed it near extinction. Once protected by the Endangered Species Act’s limitations on alligator products and hunting—as well as increased conservation of its habitat—populations recovered.
American alligators mostly live in coastal parts of the southeastern United States. They rely on fresh water to live but can tolerate salt water for brief periods of time for foraging, says Eric Krueger, TNC’s director of science and stewardship in South Carolina. “They tend to be on the outer coast, where tides promote growth of grassy wetlands where they can build nests and get in the sun.”
With only limited hunting allowed, the American alligator’s primary threat now is habitat loss caused by development and the pressure that climate change is putting on tidal freshwater areas. The Nature Conservancy has been involved in protecting the species by conserving wetlands throughout the Southeast. In South Carolina’s Ashepoo, Combahee and Edisto Basin, TNC has protected more than 83,000 acres, contributing to a combined
310,000 acres privately and publicly protected in the region. Delisted in 1987 and with an estimated population of 5 million today, the American alligator is still monitored because it closely resembles the American crocodile, which overlaps with its range in southern Florida and is listed as endangered.
American alligators help balance ecosystems by keeping populations of species lower on the food chain in check. Today they face a growing new threat: clashes with humans. Though they don’t typically attack people,
alligators are attracted to stormwater ponds in developed areas. Do not leave food there, says Krueger. “Feeding them breaks down their natural fear.”
By the 1960s, peregrine falcons had vanished from the eastern part of the U.S. and had begun disappearing in the West. Their numbers dropped as a direct result of DDT, ingested through prey already carrying the pesticide. Like bald eagles, peregrine populations were devastated by a specific side effect of DDT that weakened eggshells, causing them to break prematurely under even normal amounts of pressure—like the weight of a parent’s body trying to keep them warm. Listed as endangered in 1973 under the Endangered Species Act, peregrines benefited first from the banning of DDT, and then from captive breeding programs led largely by The Peregrine Fund, a nonprofit founded in 1970 to protect its namesake from extinction. Now dedicated to conserving birds of prey worldwide, the organization no longer actively manages peregrines, says Chris McClure, Peregrine Fund’s executive vice president of science and conservation. “Peregrines are such a success story, we can take a step back and just watch from afar,” he says. The species was delisted in 1999 and now lives in almost every corner of the globe. One of the best places to spot one? Manhattan. “Peregrines need two things,” says McClure. “A cliff to breed on, and a bunch of prey.” With its abundant skyscrapers and pigeon populations, he says, “New York has both.”
This member of the Asteraceae family, known for its gold-hued blossoms and distinctive blue-green stems, can grow up to 7 feet tall. Eggert’s sunflower is native to Alabama, Kentucky and Tennessee. It was listed as threatened in 1997, when it could only be found in 14 counties scattered across those states. Preferring open, grassy areas and thickets, the plant was primarily threatened by habitat degradation in the form of commercial and residential development as well as land conversion for agriculture. But conservation efforts—including reduced use of herbicides and delayed mowing along roadsides where Eggert’s sunflower grows—have been so successful that, just eight years after being listed, it was delisted.
Virginia Northern Flying Squirrel
Glaucomys sabrinus fuscus
High in the Allegheny mountains of West Virginia and Virginia, the nighttime movements of foot-long flying squirrels are a sign that all is well in this Appalachian world. The nocturnal mammal depends on a specific, truffle-like fungus as its primary food source, and that fungus in turn depends on the roots of healthy red spruce trees. “It’s a web, not a linear relationship,” says Mike Powell, director of land management and stewardship for TNC in West Virginia. The squirrel propagates the fungus through its droppings, exemplifying a symbiotic relationship reflective of a healthy ecosystem. It wasn’t always this way though. Logging activity in the 1800s destroyed hundreds of thousands of acres of red spruce, replacing the squirrel’s once-cool, moist habitat with a sun-baked expanse prone to flooding and erosion. “It was described as the greatest spruce forest known to man,” says Powell, “but once it was discovered by industrial loggers, it disappeared very quickly—almost every standing spruce was cut.” By 1985, the squirrel was of such concern that it was listed as endangered, setting into motion a range of conservation projects and partnerships. Among TNC’s collaborators is the Central Appalachian Spruce Restoration Initiative. The Nature Conservancy has also protected thousands of acres of these forests and, to ensure they remain undisturbed by mining, purchased the mineral rights for 57,000 acres on Cheat Mountain as well as 4,000 surface-rights acres in high-elevation areas. “Collectively,” says Powell, “we have planted over 2 million red spruce and associated trees.” That equates to about 70,000 acres in which red spruce is once again the dominant canopy. Delisted in 2013, the squirrel, like so many species, is now threatened by climate change and will require a habitat that is more resilient than ever if it is to survive. These forests have been through several stress points, says Powell. “We’re working as hard and as fast as we can to restore them.”
Soon To Be Listed?
Several animals are currently under consideration for inclusion on the endangered species list. Here are three potential candidates. Click the images to learn more.
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About the Creators
Illustrator Teagan White is an artist whose work has appeared in numerous books and gallery shows and often focuses on biodiversity loss.
Writer Catherine Zuckerman is a senior writer for Long Story Short Media who recently wrote about kelp forests for Nature Conservancy’s summer issue.