The Passenger Pigeon was once the most abundant bird in North America, moving through the landscape in massive flocks that darkened the sky. Its demise has become a sadly familiar tale: Widespread hunting in the latter part of the 19^th century took a fast and lethal toll, and the last Passenger Pigeon, named Martha, died in 1914 at the Cincinnati Zoo.

An exhibit at Smithsonian's National Museum of Natural History aims to make visitors aware of the reasons behind the relatively recent extinctions of the Passenger Pigeon and three other iconic North American birds: the Carolina Parakeet, Heath Hen, and Great Auk. Featuring mounted specimens, eggs, historic books and illustrations, and informative graphics, the small exhibit, “Once There Were Billions: Vanished Birds of North America,” offers compelling portraits of these four remarkable birds.

As a conservationist, however, my reaction to the exhibit was also one of grief: for the loss of these fascinating avian species and the impending loss of many more, all due to the actions of humans. We are, unfortunately, in the midst of a major worldwide extinction event, and some scientists have begun to write about the grief experienced by contemporary conservationists.

Passenger Pigeons, John James Audubon

But to be a conservationist, one must also be an optimist. We must have hope that our actions will make a difference for the creatures and habitats we value. We must believe we can stop and reverse the negative impacts of civilization, and that we can retain some semblance of nature in a world increasingly dominated by human influences.

As this fascinating exhibit made clear, we have indeed lost much. But times have changed, and scientific research has evolved dramatically. Hopefully, we can prevent this from happening again.

Protecting Habitat

While we know little about the reasons behind the extinction of the gregarious Carolina Parakeet, its demise was likely due to habitat loss. The bird's range collapsed with the westward expansion of settlers, who cleared much of the eastern and southern deciduous forests and also shot the bird as a crop pest.  The last captive bird died in 1918.

Carolina Parakeets, John James Audubon

Lesson: To survive, birds need critical habitat during all stages of their lives. And when conflicts between humans and wildlife occur, we must manage them with the goal of sustaining wildlife populations—not eliminating them.

Small Populations at Risk

Heath Hens were a common species that once inhabited a large swath of coastal North America, from southern New Hampshire to northern Virginia. Sought for food from colonial times through the 1800s, this intense and unregulated hunting proved to be more than the population could withstand. By 1870, there were no more Heath Hens anywhere on the mainland United States.

Health Hen, James Turvey

Yet a small population of 300 or so birds survived on Martha's Vineyard, Mass. In 1908, officials banned hunting and created the Heath Hen Reserve. The population grew to nearly 2,000 birds. But a series of unfortunate and unforeseen events—including fire and severe winters—knocked the population down again. By 1927, there were only around a dozen Heath Hens left. The last bird was seen in 1932.

Lesson: Conservation cannot succeed if—no pun intended—we put all of our eggs in one basket. Unanticipated events can have devastating effects and it is important to protect against these unforeseen calamities.

Perils of a Prized Commodity

Great Auks were flightless birds that lived exclusively on rocky, isolated islands. Their limited habitat probably made them vulnerable to extinction, but other factors hastened their decline.

Great Auk, John Gould

Although Native Americans and early European explorers used the Great Auk for food, extinction loomed only once the bird's down became a prized commodity in Europe: by the mid-16^th century, the European population was gone. European museums and private collectors snapped up remaining birds, and the last Auk was seen in 1852.

Lesson: Unregulated commercialized hunting driven by consumer demand is a death knell for wildlife. Although some birds with limited distributions or specialized habitat requirements can persist for thousands of years in tiny populations—Millerbirds, for instance, on Hawaii's Nihoa Island—others can be vulnerable to extinction when there are clear and present threats.

More Commitment, Greater Hope

Species extinctions are not inevitable and can be avoided, says Mike Parr, ABC's Chief Conservation Officer and Chair of the Alliance for Zero Extinction.

“The only reason we will continue to lose species in the future is if we fail to mobilize sufficient resources to counter threats,” Parr says. “Hundreds of species survive today that would not be here if not for conservation programs.”

The extinction of the Passenger Pigeon, Carolina Parakeet, Great Auk, and Heath Hen occurred because humans failed to understand the consequences of their actions, says Pete Marra, head of the Smithsonian Migratory Bird Center.

“Today, we don't have such excuses,” Marra says.

Millerbird, Sheldon Plentovich

At ABC, we take important steps every day to prevent extinctions and safeguard the Americas' rarest bird species. By conserving and restoring critical habitats; addressing threats such as free-roaming cats, toxic pesticides, and collisions with wind turbines; and cultivating strong partnerships with likeminded conservation groups, we focus on a hopeful future—for birds, other wildlife, and people.

Michael Hutchins earned his Ph.D. in animal behavior at the University of Washington in Seattle. Prior to ABC, Michael served as Director/William Conway Endowed Chair, Department of Conservation and Science, at the Association of Zoos and Aquariums for 15 years, and Executive Director/CEO at The Wildlife Society for seven years. He has authored over 220 articles and books on various topics in wildlife science, management, and conservation, and has traveled to over 30 countries to pursue his passion for conservation.