Sometime in the summer of 1914, probably on September 1st but perhaps a few days earlier, the last passenger pigeon on earth expired. The bird, named Martha, had spent most of her life at the Cincinnati Zoo. Up until a few years before her death, she had a companion, George, who shared her ten-by-twelve-foot cage. Whether the two ever tried to mate is unknown. Like the Washingtons, they remained without heirs.

At the time, Martha’s death was seen as a remarkable and tragic event; just a few decades earlier, the passenger pigeon had been the most abundant bird in North America, with flocks so immense that they blocked the noonday sun. When Martha’s lifeless body was discovered—it was claimed that she’d died surrounded by “a hushed group of distinguished ornithologists,” but more likely she died alone—it was taken to the Cincinnati Ice Company, frozen into a three-hundred-pound block, and shipped to the Smithsonian.

A century later, Martha’s demise seems a good opportunity to reflect on what Rachel Carson called “the problem of sharing our earth with other creatures.” And, indeed, a group called the Passenger Pigeon Project is hoping to use the centennial of Martha’s death to stage a series of events to remind Americans “of humanity’s ability to exhaust seemingly endless riches.” But the occasion is also being used to promote another idea—more upbeat or more dismaying, depending on your perspective. This is the notion that the passenger pigeon can be brought back to life, along with the great auk, the aurochs, the Tasmanian tiger, and—best, if also creepiest—the woolly mammoth. (I wrote about these and other lost species in “The Sixth Extinction.”)

Bringing back the passenger pigeon has become a pet project of Stewart Brand, who founded and edited the Whole Earth Catalog and who now runs a group called Revive & Restore. Last month, the group’s efforts were the subject of a cover story in the New York Times Magazine. Brand, who is seventy-five, told the author of that story, Nathaniel Rich, that he hoped to see the birth of a baby woolly mammoth within his lifetime.

“I would guess that within a decade or two, most of the major conservation organizations will have de-extinction as part of the portfolio of their activities,” Brand said.

There are a lot of potential problems with de-extinction, starting with the fact that, in any rigorous way, it’s probably impossible. Recent advances in paleogenetics have made it feasible to reassemble the genomes of recently extinct animals, like the passenger pigeon and even the mammoth. But the results are inexact—there will always be uncertainties. And even then things get really tricky.

The nearest living relative of the passenger pigeon is a bird called the band-tailed pigeon, which lives in the western United States and in Canada. The theory behind Revive & Restore’s resurrection effort—which, it should be noted, has a staff of one—is that, with some very sophisticated genetic slicing and dicing, a band-tailed pigeon embryo could be converted into a passenger pigeon embryo. This embryo could then be transferred to a band-tailed pigeon egg and raised by band-tailed pigeon parents.

However—as Ed Green, a biomolecular engineer who worked on the Neanderthal Genome Project, pointed out to Rich—replicating an animal’s genome is not the same as replicating an animal. “There are a million things that you cannot predict about an organism just from having its genome sequence,” Green said. Baby birds learn a lot from older birds, and the band-tailed pigeon’s way of life is very different from the passenger pigeon’s. Thus, it seems, even if a genetic replica of a passenger pigeon could be created (a very big if), the best that could be hoped for is a bird that’s something like a passenger pigeon and something like a band-tailed pigeon—a Band-Aid pigeon, you might call it.

One or two or even several thousand Band-Aid pigeons are a far cry from the billion-strong flocks that greeted the first European colonists to settle North America. (William Strachey, who arrived in Virginia in 1610, described pigeons filling the sky “like so many thickned clowdes.”) It was the size of these flocks that mattered to the forest ecosystem; animals do not exist on their own.

And this is the real weakness of the whole de-extinction project—its fatal flaw. To bring a lost animal back because people might like to see it, or because they might feel better imagining that it’s not entirely gone, or just to demonstrate that it can be done is to re-create a version of poor Martha, who, in her waning years, drew large crowds of curiosity-seekers to the Cincinnati Zoo. It’s a vanity project and nothing else.

As more and more species go the way of the passenger pigeon, de-extinction is bound to attract more attention. There may be no real harm in fooling around with the passenger pigeon genome, as Brand wants to do. But it shouldn’t be mistaken for recovering what’s been lost.

Read Elizabeth Kolbert on mass extinction and Jonathan Rosen on the fate of the passenger pigeon.

Photograph: Smithsonian Institution Archives.