The Endangered Species Act at 50 & What’s Next for Wildlife

The Endangered Species Act has protected a host of wildlife across the U.S. in 50 years, but plenty of work remains

  • By Brianna Randall // Photos by Joel Sartore
  • Conservation
  • Sep 27, 2023

Grizzly Bear, Ursus arctos horribilis, THREATENED | Some 50,000 grizzly bears once roamed across the entire western United States south into Mexico. But by the 1930s—after decades of government-sponsored killing by European settlers—the bears had vanished from 98 percent of their range in the Lower 48, with a population of 700 to 800 outside Alaska and Canada. Listed in 1975 under the Endangered Species Act as threatened—or ”likely to become endangered in the foreseeable future”—grizzlies are recovering in many parts of their range, with nearly 2,000 at last count.

THE SIGHT OF A BALD EAGLE GLIDING OVERHEAD, white head framed against the blue sky, is sure to spark a sense of awe—and perhaps a breath of gratitude. An emblem of strength, courage and freedom, our country’s national symbol was once nearly extinct in the Lower 48.

In 1776, when the country was founded, about a half-million bald eagles soared above what’s now the continental United States. But beginning in the late-1800s, the population steadily declined as eagles fell victim to habitat loss, deliberate killing and, starting in the 1940s, the widespread use of DDT—a synthetic pesticide that washed off the land into waterways and contaminated fish that eagles eat. By 1963, only 417 breeding pairs remained in the country outside Alaska.

Today, however, some 316,700 eagles once again soar the nation’s skies—thanks in large part to the Endangered Species Act (ESA), which catalyzed a number of eagle conservation measures, including protection for critical habitat, a ban on DDT and captive breeding and reintroduction programs.

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An image of two bald eagle chicks in a nest.

Bald Eagle, Haliaeetus leucocephalus, DELISTED | Chosen as a symbol for the U.S. national emblem in 1782—with its image on everything from passports to quarters—the bald eagle is a conservation success story. Victims of habitat loss, deliberate killing and the synthetic pesticide DDT, the eagles were down to just 417 breeding pairs in the Lower 48 by the 1960s. Thanks to protections spurred by the ESA, bald eagles rebounded, and in 2007, the U.S. Fish & Wildlife Service removed them from its list of threatened and endangered species.

Signed by President Richard Nixon on December 28, 1973, the ESA protects plants and animals at risk of going extinct, in part by mandating the creation of a list of endangered and threatened species. Species are considered for listing when federal scientists determine ESA protection is needed or when the government receives a petition from an individual or organization requesting a species’ addition. If scientists determine listing is warranted and the government adds the plant or animal to the list, either the U.S. Fish & Wildlife Service (FWS) or, for most marine species, the National Marine Fisheries Service must create a plan for aiding its recovery.

Celebrating its 50th anniversary this year, the ESA has saved hundreds of animals that once teetered on the brink of extinction. Without its protections, we might not have gray whales spouting off our coasts today or alligators roaming mangrove swamps, brown pelicans gliding above beaches or grizzly bears lumbering through western mountains. “The ESA is one of the most important foundational conservation laws in our country,” says Mike Leahy, senior director of wildlife policy for the National Wildlife Federation.

According to a 2019 study published in PeerJ, the ESA has prevented the extinction of some 291 species since the law was passed in 1973. Species whose extinctions were averted range from large, well-known animals such as the California condor and Hawaiian monk seal to a host of lesser-known species like the pinky-sized Oregon chub, a minnow.

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An image of a gray wolf.

Gray Wolf, Canis lupus, ENDANGERED | Once widespread across most of North America, the gray wolf was heavily hunted—subsidized in large part by federal predator-control programs—and vanished throughout nearly all of its historic range. In 1978, the species was listed as endangered in the Lower 48 and Mexico (except Minnesota, where it was listed as threatened). Since then, the wolf has made a remarkable recovery in the Northern Rocky Mountains, ultimately coming off the endangered species list throughout the region.

One of the most-celebrated ESA success stories has been the effort to bring gray wolves back to the Northern Rockies, particularly Yellowstone National Park, where wolves had been missing since 1926. After the species was listed as endangered in 1974, FWS, the National Park Service and state wildlife agencies partnered to relocate 41 wolves from wild populations in Canada and northwestern Montana into the park in the 1990s. By 2008, FWS biologists estimated that 1,639 wolves roamed through Montana, Wyoming and Idaho—five times higher than the minimum population goal in the species’ recovery plan.

This happy ending did not stop with wolves: Reintroducing the keystone predator sent benefits rippling across the 22-million-acre Greater Yellowstone Ecosystem. The gray wolf’s absence, for example, had allowed Yellowstone’s elk to munch freely on cottonwoods, willows and aspens without fear of predation. This was bad news for beavers, which rely on riparian trees for food and shelter. Just one colony of beavers remained in the park in 1995. Once wolves rebounded, keeping elk on the move, riparian vegetation rebounded, improving habitat for beavers, cutthroat trout and other species.

Reintroducing gray wolves also produced more food for a host of animals that scavenge the predators’ kills. According to a 2003 study in the Journal of Animal Ecology, Yellowstone’s wolves consume only 40 to 80 percent of their elk kills, leaving plenty of leftovers to sustain other wildlife, from ravens, magpies, and bald and golden eagles to coyotes, grizzly and black bears and at least 57 species of beetles.

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An image of a black-footed ferret.

Black-Footed Ferret, Mustela nigripes, ENDANGERED | Until a tiny population was found in 1981, the black-footed ferret was considered extinct, a victim of habitat loss and the attempted eradication of the carnivores’ prairie dog prey by ranchers who thought the rodents competed for grass livestock eat. Thanks to captive breeding and reintroduction, small wild populations remain. One new strategy, aimed at increasing these populations’ genetic diversity, was cloning a female ferret (right) from another female who’d never passed on her own genes.

Despite the law’s success at preventing extinctions, however, relatively few listed species have ever been declared sufficiently recovered to remove from the list—a total of just 54 species since the act was passed a half-century ago, according to a 2022 study published in Plos One.

Take the endangered black-footed ferret. Decimated by habitat loss and landowners killing off their prey—prairie dogs—these sleek little carnivores were thought to be extinct until a small population was discovered in Wyoming in 1981, forming the core of a captive-breeding colony a few years later. Since 1991, thousands of ferrets have been captive-bred and reintroduced to 33 sites in eight western states, Canada and Mexico. But while the animals’ numbers peaked at about 700 in 2008, FWS estimates there are only a few hundred now.

Meanwhile, ferrets face many newer threats, including inbreeding and—especially—nonnative sylvatic plague. To fight the plague and the fleas that spread it, biologists are experimenting with vaccines and insecticides. To increase the ferrets’ genetic diversity and prevent inbreeding, FWS in 2020 cloned a female ferret from another female that had never given birth (and therefore never passed on her genes), but the cloned female also was unable to reproduce. According to David Wilcove, a Princeton University conservation biologist and co-author of the Plos One paper, it’s possible ferrets will never fully recover, “but there’s no question that, without the ESA, this marvelous animal would be extinct today.”

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An image of an American Alligator.

American Alligator, Alligator mississippiensis, THREATENED | Found only in the United States, the American alligator ranges across coastal wetlands of the Southeast, from North Carolina west to Texas and south to Florida. Beginning in the 1860s, the luxury leather industry’s demand for hides led to widespread hunting of alligators and drastic population declines. Federally protected as endangered in 1967 under a law that preceded the ESA, alligator numbers bounced back once alligator farming began and hunting was temporarily put on hold.

In their study, Wilcove and his colleagues examined several possible causes of low species recovery rates. Focusing on 970 species listed between 1992 and 2020, they concluded: “Most species are not receiving protection until they have reached dangerously low population sizes.” Leahy likens the ESA to an “emergency room, where you’re doing whatever it takes to save a species, but it may be too late.”

Emergency measures came too late to save mountain caribou in the Lower 48. Once roaming northeastern Washington, northern Idaho and northwestern Montana, the continent’s southernmost herds had dwindled to fewer than 50 individuals by 1983 when the population was listed as endangered.

Three decades later, Canadian wildlife officials captured the last four caribou from the herds, moving them to join larger groups in British Columbia. Ray Entz, director of wildlife and terrestrial resources for the Kalispel Tribe in Washington state, says the Tribe hopes to eventually relocate caribou back to this country. The animals are an important part of the Tribe’s “traditional culture and diet and spirituality,” says Entz. “In dire times, during severe winters or when food stores were low, caribou sustained us. Our view is that caribou are now in that same dire space, and it’s our turn to sustain them.”

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An image of a brown pelican.

Brown Pelican, Pelecanus occidentalis, DELISTED | Inhabiting beaches and lagoons along Atlantic, Pacific and Gulf coasts, brown pelicans hovered near extinction twice: devastated first by hunting for feathers then by the pesticide DDT, which contaminated fish the birds feed on and resulted in deadly thinning of their eggshells. Listed as endangered in 1970 under the ESA’s predecessor, brown pelicans have recovered, thanks to habitat conservation and—especially—the banning of DDT. The species was removed from the endangered species list in 2009, and today its populations are still increasing.

Another shortcoming of the ESA is inadequate funding. For its endangered species work, FWS receives $70 to $80 million in federal funding a year—compared to a whopping $766 billion the government spent on national defense in fiscal year 2022. Like the black-footed ferret, “many listed species, from the right whale to the California condor, will remain conservation reliant; they will always need our care to survive,” says Wilcove. Even when recovery is possible, “it’s expensive and takes a really long time,” he adds. “Funding for the ESA is not commensurate with what is needed.”

Shoren Brown, vice president of public affairs for The Conservation Alliance—a group of 270 outdoor-related companies that fund and advocate for the protection of North America’s wild places—and a former NWF staff member, agrees. “Conservation without funding is just an idea; it’s not implementation,” he says. Since the ESA passed in 1973, the threats to our landscapes and wildlife have increased “by orders of magnitude” without the necessary accompanying investments.

Not surprisingly, limited federal funding often prioritizes charismatic animals such as ferrets, whales and eagles. Cash-strapped state wildlife agencies, meanwhile, focus much of their funds on game species that bring in hunting or fishing revenue they use to finance their own wildlife conservation work, including recovery efforts for species on state endangered lists. That leaves hundreds of endangered species—from snails and shellfish to wildflowers and insects—with little to no funding and makes them more vulnerable to extinction.

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An image of a monarch butterfly.

Monarch Butterfly, Danaus plexippus, CANDIDATE | Threatened by pesticides, climate change and habitat loss—specifically, loss of the native nectar and host plants the insects and their caterpillars need—our most-recognized butterfly has been in decline since the mid-1990s and has been proposed for listing as threatened. Fortunately, hundreds of individuals and organizations, including NWF, have stepped up to help monarchs recover by creating and restoring native pollinator habitat across the country.

One way to protect a broader array of species—and increase funding for all at-risk plants and animals—would be to pass the Recovering America’s Wildlife Act (RAWA), say conservationists. Introduced in the U.S. Senate in March 2023, the bipartisan bill would provide $1.3 billion a year to state wildlife agencies to fund wildlife conservation efforts. That funding would cover costs for 75 percent of activities outlined in State Wildlife Action Plans, benefiting more than 12,000 species of concern listed in the plans. Many of those species also are on the states’ own lists of endangered species or protected under the ESA.

In addition, the law would provide $97.5 million annually to Tribes, which historically have been left out of reliable sources of funding for wildlife conservation. Passing the act “would be an intentional step towards co-stewardship and equity and also ensure Tribes have a seat at the table to meaningfully engage in and implement conservation decisions that impact their fish and wildlife relatives,” says Julie Thorstenson, executive director of the Native American Fish and Wildlife Society.

Leahy says one of the act’s most important goals is to keep common species common and protect at-risk species through “proactive conservation,” reducing the number that require listing as federally endangered. While the ESA has been a great resource to prevent species extinctions, Rebeca Quiñonez-Piñón, director of the Climate-Resilient Habitat Program and monarch recovery strategist for NWF, believes we need to do more to help at-risk species before they need ESA protection. “We can better support imperiled species in our daily lives,” she says. “For monarch butterflies, that could mean reducing the use of pesticides in your yard or planting native milkweeds and nectar plants.”

Monarchs are a good example of how the law’s proactive conservation could work. Battered by habitat loss, pesticides and climate change, these much-beloved insects have declined by 90 percent east of the Rocky Mountains and by 99 percent in the West since the mid-1990s. Proposed for federal listing as threatened in 2014, the species remains unprotected by the government. Although an FWS assessment in 2020 concluded that listing was warranted, further action was put on hold while the service focuses on “higher-priority listing actions.”

Nonetheless, a bevy of states and nonprofits, including NWF, are already engaged in vital monarch conservation efforts nationwide. NWF’s Certified Wildlife Habitat® and Schoolyard Habitats® programs, for example, help participants create pollinator-friendly outdoor green spaces at homes, schools and businesses. In Texas, 12 schools have participated in the Monarch Heroes environmental education program, where students planted native milkweed and nectar plants and contributed observations to research. From Minnesota south to Texas, along the U.S. portion of the monarch’s central flyway between Canada and Mexico, NWF worked with state transportation departments to promote pollinator habitat in the rights of way along Interstates 77 and 83. And more than 1,000 U.S. mayors have taken the Federation’s Mayors’ Monarch Pledge™, committing to foster pollinator habitat in their cities. Collectively, these and other efforts have helped protect, create or restore millions of acres of habitat for the iconic insects.

To spawn similar action for less-popular wildlife, Leahy stresses the importance of passing RAWA—especially this year, as we celebrate the 50th anniversary of the ESA. The most significant federal investment in wildlife conservation since the ESA, “RAWA would tap into the energy and the expertise of the states, Tribes and territories and set them up with the resources they need to keep species from becoming endangered, which is not a fate we want for any of our wildlife,” he says.

NWF priority

Protecting Imperiled Species

The National Wildlife Federation works to defend, strengthen, fund and ensure the effective implementation of the Endangered Species Act. To better support all wildlife species, NWF also champions the proposed Recovering America’s Wildlife Act, which would invest $1.4 billion annually to help states and Tribes keep wildlife populations healthy. Learn more at

Montana-based writer Brianna Randall is a frequent contributor. National Geographic photographer Joel Sartore focuses on portraits of wildlife in human care.

More from National Wildlife magazine and the National Wildlife Federation:

Life Keepers »
A Game Changer Awaits Passage »
Blog: Endangered Species Act »

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