While birds may appear abundant — we see them every day, right? — recent studies point to an unsettling truth: Avian populations are declining. In just the last 50 years, nearly a third of all U.S. and Canadian birds have disappeared. As it stands, one out of every eight bird species in the world faces extinction.

But that doesn't mean all birds are in trouble: Population declines are disproportionate, making some birds much rarer than others.

Birds in the United States are no exception: We've already lost a number of species to extinction and are close to losing more. While there are many birds with limited or declining numbers that could be considered “rare,” we highlighted only those species with the smallest populations in the continental U.S. — the rarest of the rare — ranking them by population from largest (relatively speaking) to smallest.

Most of these birds are surviving thanks to the heroic, decades-long efforts of conservationists. But that doesn't mean the work is finished: The future of these rare birds depends on our commitment to their long-term survival. To learn more about how you can help birds, make sure to continue scrolling below our list. You'll also find more information about the data used and how we compiled this list.

5. Gunnison Sage-Grouse (Centrocercus minimus)

The Gunnison Sage-Grouse holds special distinction as the first new bird species formally described to science in the United States since the 19^th century. But this federally Threatened species isn't new: It and the Greater Sage-Grouse were assumed to be the same bird until 2000, when they were officially split into two species, based on differences in their behavior, physical attributes, and vocalizations. Both inhabit similar sagebrush habitat and engage in equally spectacular courtship displays, but the Gunnison is the rarer of the two. Absent from approximately 90 percent of its former range, only 4,800 Gunnison Sage-Grouse remain in western Colorado and eastern Utah. Threats to this rare and declining bird are numerous, including habitat loss, drought, disease, and climate change. As this once-numerous species edges toward extinction, its survival is increasingly dependent on conservation efforts.

4. Kirtland's Warbler (Setophaga kirtlandii)

Of the more than 50 warbler species found in the U.S. and Canada, none have ranges smaller than the Kirtland's Warbler. That's because these rare birds have very specific needs when it comes to choosing breeding grounds: They almost exclusively inhabit large, dense stands of young Jack Pine in Michigan (as well as nearby areas of Wisconsin and Ontario). When these forests, historically maintained by fires, began to disappear due to fire suppression and evolving logging practices, so did the Kirtland's Warbler. Although it's unlikely these birds were ever very numerous, their numbers dropped to alarming levels in the 1970s, warranting listing under the Endangered Species Act. At its nadir in the 1980s, the entire male breeding population consisted of only 167 individuals. Since then, intensive habitat improvement efforts, along with control of Brown-headed Cowbirds, which parasitize Kirtland Warbler nests, have helped the species rebound. Although the Kirtland's Warbler has been removed from the endangered species list and its population now totals 4,490 individuals, it remains one of the rarest songbirds in North America and requires continued assistance to ensure its long-term survival.

3. Island Scrub-Jay (Aphelocoma insularis)

Found on a single island off the coast of southern California, the Island Scrub-Jay has the smallest range of any North American bird species and, not surprisingly, one of the smallest populations. Once thought to total more than 12,000 individuals, the population of this Near Threatened species is now estimated to be only 2,300. Genetic evidence suggests that the Island Scrub-Jay diverged from the California Scrub- Jay, its closest relative (and a widespread species), 150,000 years ago. Because the Island Scrub-Jay doesn't migrate, its survival is deeply intertwined with the quality of oak and chaparral habitat on Santa Cruz Island, which has been improving since the removal of sheep in the 1980s. Even so, these rare birds remain in a precarious position due to their isolated location, vulnerable to a number of possible threats including disease and land-use changes. These dangers may only increase in the future: As temperatures rise, scientists worry that the West Nile Virus, spread by mosquitoes, could eventually reach Santa Cruz Island, further imperiling the Island Scrub-Jay. 

2. Whooping Crane (Grus americana)

Tall, stately, and extremely rare, the Whooping Crane holds a unique place in the hearts of many. This federally Endangered species had been uncommon since the 19^th century, but decades of extensive hunting and habitat loss led to a close brush with extinction in the 1940s, when the total population dipped below two dozen. Conservationists, however, have made extraordinary efforts to save this regal bird by means of captive breeding, habitat management, and even an inventive program teaching young birds to migrate by following ultralight aircraft. As a result, Whooping Crane populations now total approximately 650, including a wild population that migrates between Canada and Texas; three introduced populations; and a captive group of 160 birds. While its population has been bolstered, the Whooping Crane isn't out of danger, and conservationists continue providing extensive support. Modern threats include powerline collisions, extreme weather events, and sporadic shootings.

1. California Condor (Gymnogyps californianus)

The California Condor isn't just the largest bird in North America, it's also the rarest. Although these Critically Endangered birds once roamed much of prehistoric North America, their population dwindled to a mere 22 birds in the 1980s. In years past, the condor's decline was fueled by hunting as well as poisoning from strychnine and lead ammunition found in the carcasses these scavenging birds consumed. While hunting and strychnine are no longer the species' main threats, lead poisoning remains a significant danger. Despite this, California Condor numbers are gradually on the rise thanks to successful conservation efforts, which include captive breeding, feeding, and lead-testing programs. This comeback, however, has been slowed by the fact that these long-lived birds reproduce slowly: Females produce only one egg every one to two years. Consequently, the number of California Condors in the wild still numbers fewer than 240, with another 160 birds in captivity. Because these numbers remain so low, intensive recovery programs continue. Thanks to reintroduction efforts, these massive birds are now found in California, Utah, Arizona, and Baja California in Mexico.

Get Involved

Policies enacted by the U.S. Congress and federal agencies, such as the U.S. Fish and Wildlife Service, have a huge impact on America's birds. You can help shape these rules for the better by telling lawmakers to prioritize birds, bird habitat, and bird-friendly measures. To get started, visit ABC's Action Center.

Many of the rarest bird species in the Western Hemisphere remain relatively unknown. You can learn more about these birds and the threats they face by signing up for ABC's Bird of the Week email series, which frequently highlights these fascinating birds.

American Bird Conservancy and our Migratory Bird Joint Venture partners have improved conservation management on more than 6.4 million acres of U.S. bird habitat — an area larger than the state of Maryland — over the last ten years. This is a monumental undertaking, requiring the support of many, and you can help by making a gift today.

Our Rare Bird List

Our list includes only species that live year-round, winter, or breed in the continental U.S. It does not include imperiled subspecies. Nor does it include rare birds found in Hawai'i or rare birds found in other parts of the Western Hemisphere. 

For most species, we relied on global population numbers from Partners In Flight's Population Estimates Database. For the Whooping Crane, we drew on estimates from the International Crane Foundation.

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Joe Lowe is ABC's Director of Digital Communications. He holds has an MS in Journalism from Ohio University and Masters in Natural Resources from Ohio State University.