THE BLOG
10/08/2013 09:46 am ET | Updated Dec 08, 2013

Is Extinction Forever? Or Is the Passenger Pigeon Waiting in the Wings?

John James Audubon "was struck with amazement" at the darkened skies caused by the birds. The man who would become famous as an artist of nature was, not surprisingly, himself a naturalist. Yet his efforts to document the flock's numbers were futile.

"The birds poured in in countless multitudes," Audubon would write. "The air was literally filled with pigeons; the light of noonday was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow; and the continued buzz of wings had a tendency to lull my senses to repose."

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Painting of passenger pigeons, John James Audubon, 1824.

Rarely has abundant poop led to serenity, but in 1813 Audubon was witnessing the spectacle of what was then the most abundant bird on earth: the passenger pigeon. Billions moved across our boundless eastern deciduous forests, feeding on the ample store, or "mast," of nuts from acorns, beechnuts, chestnuts, and the like.

By the end of that century, the passenger pigeon was all but extinct.

It is probably the most dramatic extinction story ever witnessed. Yet now there is interest and even the possibility of bringing the most famously extinct bird back. By retrieving DNA from museum skins and using emerging genetic techniques with the passenger pigeon's closet living relative, the band-tailed pigeon, we might well witness again the passenger pigeon.

Great, right? I am not so sure. Of course I wish I had had a chance to see the magnificent dark clouds of birds that Audubon saw. But the passenger pigeon is gone because the world that it belonged to is no more. The ecological challenges I grapple with daily as a conservationist today give me pause as I consider the idea of bringing back long-lost species and returning them to the wild.

We are in a world of hurt in conservation. Many species are at risk of extinction and the problems and challenges only grow. Particularly dispiriting is the fact that financial support for species conservation is waning even as the threats to so many species grow.

Genetically re-engineering passenger pigeons (or wooly mammoths, or tyrannosaurs) sends a misleading message: Extinction is not forever! We can bring anything back. How will public perception of wildlife and conservation change with the re-emergence of extinct species? We will never truly lose a species, the argument goes, as long as we have the DNA.

Another concern: I do enjoy seeing animals in zoos, particularly those I haven't seen in the wild.

The organization I work for, the Wildlife Conservation Society, maintains its headquarters at the Bronx Zoo. On a recent visit there, I greatly enjoyed visiting our "World of Birds" exhibit. There I can see the grey-winged trumpeter up close. Trumpeters are highly social, large terrestrial birds of northern Amazonia. Through the zoo I can get a sense of the bird and take inspiration from how this "piece" (this species) fits in the "whole" (its Amazon habitat).

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Grey-winged trumpeter. © Steve Zack/WCS

Here's my point. Recreating the passenger pigeon recreates a "piece," but their "whole" is long lost. The world of the passenger pigeon was the immense, intact, and uncut forest landscape of eastern North America that no longer exists. More specifically gone is the massive mast of food produced by this forest that this highly social and mobile animal thrived upon at particular points in time and space.

The billions of birds would darken skies in search of this mast and rear their single young from nests. Then they would move and find more masts and breed again. Breeding twice across large geographies with large food stores was key to their survival. That world is gone, gone. Gone is the American chestnut, the beautiful American Elm. Gone is that "whole."

Natural history museums can capture our imagination by preserving the memory of species long gone. Zoos have the power to inspire visitors to conserve species yet with us. We risk blurring those distinctions by bringing back the passenger pigeon and other extinct species. In many cases these animals would return to a new "wild" challenged by our growing human footprint.

Like Audubon, I am struck with amazement at what was the world of the passenger pigeon. As we consider the pros and cons of de-extinction, let's learn from that lost world and engage more fully with our own to keep the species and habitats we do have left from disappearing. The better we appreciate what we have lost, the more we may cherish what remains.