If you’ve ever met a birder or ornithologist, you’ve probably heard of the elusive (and hotly debated) ivory-billed woodpecker. After years of searching for signs of the "holy grail" of birds, the US Fish and Wildlife Service (FSW) declared it officially extinct in September. 

The ivory-billed woodpecker is one of 22 species of birds, fish, mussels, and bats (and one species of plant) that were declared extinct in the US in 2021. The announcement contains the largest group of animals and plants to be moved from the endangered to extinct list under the 1973 Endangered Species Act (ESA). Since its passing, only 11 species listed in the act have ever been classified as extinct. 

This sweeping declaration is a red alert for conservation and biodiversity — but it comes as no surprise. For years now, we’ve experienced massive losses in biodiversity due to climate change, disease, pollution, invasive species, and loss of habitat as a result of agriculture and industrialization. 

A 2019 Global Assessment Report on Biodiversity and Ecosystem Services from the United Nations Educational, Scientific, and Cultural Organization (UNESCO) and Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) examined the main causes of biodiversity change and loss.

The report, which UNESCO Director-General Audrey Azoulay said put the world “on notice,” found that human activities “threaten more species now than ever before” and that the global rate of species extinction is already “at least tens to hundreds of times higher than it has averaged over the past 10 million years.”

Around the world, an estimated 1 in 4 species of plants and animal groups are vulnerable, which means about 1 million species are facing extinction, some within decades. 

The 23 species declared extinct by the FSW this year may also come with little surprise. Some species have been assumed extinct for decades, with their last sightings dating as far back as 1899. While the search for some might be over, the fight to preserve their habitats and the habitats of those still endangered should carry on.

“The loss of species, ecosystems, and genetic diversity is already a global and generational threat to human well-being,” said Sir Robert Watson, former chair of the IPBES. “Protecting the invaluable contributions of nature to people will be the defining challenge of decades to come. Policies, efforts, and actions — at every level — will only succeed, however, when based on the best knowledge and evidence.” 

Here are the 22 animals in the US that were declared extinct in 2021 — and how we should take action now to protect biodiversity. 

1. Kaua’i ‘o‘o

The only way to hear the Kaua’i ‘o‘o sing now is through recordings. The bird, once native to the Hawaiian islands, was last seen in 1987 and listed as endangered by the FWS in 1967. At least 32 species of birds native to Hawai’i have gone extinct since 1778. Islands are particularly vulnerable to species loss due to their isolation. The introduction of foreign diseases, rodents such as rats and mongooses, and cats play a large part in the loss of species.

2. Maui ‘ākepa

The Maui ‘ākepa was a Hawaiian honeycreeper whose last confirmed sighting was in 1970. Over 50 species of honeycreepers used to live in Hawai’i; now there are only 17 species left. Of the 23 plant and animal species being added to the extinct list this year, 11 are from Pacific islands, Guam and mostly Hawai’i. 

3. Kaua’i nukupu’u

The last credible sighting of the Kaua’i nukupu’u was in 1899, and it’s believed to have gone extinct in 1901 due to avian disease and habitat loss. Mosquitoes brought on ships were introduced to the Hawaiian islands in the 1800s and spread diseases to birds.

4. Ivory-Billed Woodpecker

Birders and conservationists have debated the presence of the ivory-billed woodpecker, which once roamed the woodlands of the southern US, for decades. The last confirmed sighting was in Louisiana in 1944. Since then, alleged sightings have been of hot debate among ornithologists and the latest declaration of extinction has its dissenters. It’s safe to say that for some, the hunt is not over. But for the FWS, the famous and long-sought “Lord God Bird” is gone for good.

5. Little Mariana Fruit Bat

The little Mariana fruit bat was last seen in Guam in 1968 and was declared endangered in 1984. It’s likely that poaching, habitat loss, and predation by the invasive brown tree snake led to its extinction. 

6. Bachman’s Warbler 

Bachman’s warbler, a yellow-breasted songbird that used to live in the southeastern US and Cuba, was declared endangered in 1967 and the last unconfirmed sighting was in Florida in 1977. Deforestation, land-clearing, and hurricanes may have wiped out Bachman’s warbler, which was once the rarest songbird in the US, for good.

7. Flat Pigtoe Mussel 

Mussels provide filtration to water systems and play integral roles in ecosystems — of the 22 animals being declared extinct this year, eight are freshwater mussels. The flat pigtoe mussel was last detected in the Tombigbee River in Mississippi, where over 40 species of freshwater mussels have been identified. The construction of the Tennessee-Tombigbee Waterway is the main factor of the mussels' disappearance. Physical destruction of habitats during building, increased sedimentation, and reduced water flow suffocated the flat pigtoe out of existence. The flat pigtoe mussel has not been collected alive since the completion of the Tennessee-Tombigbee Waterway in 1984.

8. Bridled White-Eye

The bridled white-eye, native to Guam, was last observed in 1983 and listed as endangered in 1984. Based on the available evidence, it’s assumed that the brown tree snake is responsible for the bird’s extinction. 

9. Kaua’i akialoa

The Kaua’i akialoa, a honeycreeper native to Hawai’i, was last seen in 1969 and presumed extinct in 1984. Avian disease is assumed to be the primary driver of its extinction.

10. San Marcos Gambusia

Like many other species on this list, these tiny fish were endemic to their area and were only found in the San Marcos River in Texas. The San Marcos gambusia was listed as endangered in 1980 and was last seen in the wild in 1983. The population of San Marcos gambusia was significantly decreased by pollution, farming, drought, and a cumulative effect of human activities. Extensive efforts were made through the 1970s to breed the fish through captivity but the fish hybridized leaving no pure species offspring. Attempts to locate the fish since have been unsuccessful.

11. Southern Acornshell Mussel

The southern acornshell, a mussel once found in the upper Coosa River system in Alabama, Georgia, and Tennessee, was listed as endangered in 1993 — but the last known specimens were collected in the early 1970s. Habitat modification such as clearing, sand and gravel mining, waterflow disruption, and asphyxiation from agricultural runoff all factored into the southern acornshell’s extinction. 

12. Po‘ouili

The Po‘ouili of East Maui was the most endangered group of forest birds in Hawai’i and was only discovered in 1973. In 1981, it was estimated that the Po‘ouili population consisted of only about 150 birds; in 2003, only three were known to still be in existence. Many efforts to protect the Po‘ouili and other Hawaiian birds have taken place since 1999, but even last-ditch mating efforts failed and the two last birds were seen in 2004. Like other native Hawaiian birds, the Po‘ouili is assumed to have been driven to extinction by disease, habitat loss, and introduced predators. 

13. Yellow Blossom Pearly Mussel 

The yellow blossom pearly mussel was once found in the rivers of Tennessee and Alabama. It was listed as endangered in 1976 and was last collected alive in 1967. The yellow blossom was driven to extinction by impoundments for flood control, barge canals, pollution, and other human-related changes to its habitat.

14. Scioto Madtom

The Scioto madtom, believed to be endemic to the Scioto River Basin in Ohio, was listed as endangered in 1975 and last collected in 1957. Only 18 specimens of this bottom-feeding fish have ever been collected. Its population and original habitat have been greatly reduced by pollution and strong flooding, which have practically wiped out the entire area in which they once lived. 

15. Moloka’i Creeper 

Endemic to Hawai’i, the Molokai creeper was listed as endangered in 1970 and many efforts to protect the bird and its habitat have taken place since. The creeper was common in 1907 but faced the threat of extinction by the 1930s. The last sighting of this scarlet shaded bird was in 1963. Like other extinct species in Hawai’i, loss of habitat, avian disease, and invasive predation led to its disappearance. 

16. Stirrupshell Mussel 

The stirrupshell mussel, which once lived in Alabama and Mississippi, was declared endangered in 1987 and was last detected alive in 1978. Dead specimens were observed in 1986. Like the flat pigtoe, alterations to the stirrupshell’s habitat drove the mussel to extinction.

17. Tubercled-Blossom Pearly Mussel

Once abundant in the eastern US and southern Ontario, the tubercled-blossom was listed as endangered in 1976 and due to habitat alteration, the last individual was found freshly dead in 1969. 

18. Large Kaua’i Thrush (Kamao Thrush)

The large Kaua’i thrush was listed as endangered in 1970 and by that time only had a population of 337. Due to its small population size and threats of avian disease, predation, and habitat loss, the last credible sighting of the thrush occured in 1987. 

19. Upland Combshell Mussel

Due to habitat modification, water quality degradation, and sedimentation, the upland combshell mussel was declared endangered in 1993. Once found in the rivers of Alabama, Georgia, and Tennessee, the upland combshell has not been detected for over three decades; the last known individuals were collected in the late 1980s.

20. Green-Blossom Pearly Mussel

The green-plossom pearly mussel was once found in the streams of Virginia and Tennessee and was listed as endangered in 1976. The mussel was always extremely rare and believed to have had a lifespan of up to 50 years. Due to significant alterations to its habitat, the last known detection of the species alive was in 1982.

21. Turgid-Blossom Pearly Mussel 

The turgid-blossom pearly mussel, listed as endangered in 1976, was once found in the rivers and streams of Alabama and Tennessee. The last known sighting of the mussel was of a freshly dead specimen, collected in 1972. Like the other now-extinct mussels in this list, the turgid-blossom pearly mussel was driven to extinction by habitat alterations and pollution. 

22. Maui Nukupu’u

The Maui nukupu’u was a Hawaiian honeycreeper that was listed as endangered in 1970. Endemic to the island of Maui, the Maui nukupu’u was estimated to have a population of 28 in 1980. The last sighting of the olive green and yellow bird occurred in 1996, falling victim to the same fate of the multitude of Hawaiian birds that have gone extinct since foreigners stepped foot on the islands. 

BONUS: Phyllostegia glabra var. lanaiensis

Phyllostegia glabra var. lanaiensis is not an animal — it's the only plant of the 23 species that were declared extinct this year. A perennial herb found on the island of Lānaʻi in Hawai’i, Phyllostegia glabra var. lanaiensis was a flowering mint that was listed as endangered in 1991, although its last known sighting was in 1914. Its extinction is due to the introduction of ecosystem-altering invasive plants, habitat loss, and feral herbivores.

What can we do to protect endangered species and biodiversity?

It all boils down to climate action. Climate change and deforestation are causing massive losses of habitats, changing migration patterns, and affecting reproduction. Not to mention that our global food demand directly threatens important ecosystems.

So how can we help? We can start by reducing our individual carbon footprints, eating less meat, and advocating for change. You can also look into conservation organizations to donate or advocate with. Check out this list of conservation groups here. The National Audubon Society also has a dedicated page for ways to help endangered birds.

Indigenous and local peoples are responsible for protecting 80% of the world’s biodiversity, yet are often underrepresented or excluded from the climate action decision-making table. Uplifting their voices and centering their causes is one way we can help protect Native rights and biodiversity.

Invasive species are a major threat to endangered wildlife. When introduced to new environments, alien predators eat eggs reducing native animal populations and some species of plants suffocate native plants and cut them off from sunlight with their shay leaves. According to a study from Frontiers in Ecology and the Environment, invasive species have contributed to 25% of plant extinctions and 33% of animal extinctions. When you travel, check for stowaways — they often come in the form of seeds and spores. The FWS has guides for dog owners, gardeners, hunters, and boaters for what you should do when you spot an invasive species. Get familiar with the endangered animals and invaders around you and help local conservation efforts by doing simple things like keeping your cat indoors or planting native species in your garden or around your neighborhood.

"With climate change and natural area loss pushing more and more species to the brink, now is the time to lift up proactive, collaborative, and innovative efforts to save America's wildlife," US Interior Secretary Deb Haaland told CNN.

The ESA has saved 291 species in the US since 1973, so it is entirely possible to prevent a species from going extinct before it’s too late. 

"Extinction, especially in the US, is preventable," said Teirra Curry, a conservation biologist at the Center for Biological Diversity.

But for now, we mourn the losses of 2021 with the promise that we will protect the 1 million species around the world fighting for survival.

Global Citizen Life

Defend the Planet

22 Animals That Went Extinct in the US in 2021 — and How to Take Action for Biodiversity

By Kate Nakamura