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A photo of Martha, the last passenger pigeon.

Passenger pigeons were hunted to extinction. Martha (above) was the last of the species.

Photograph by Robb Kendrick, National Geographic Creative; Taxidermic specimen, Smithsonian Institution’s National Museum of Natural History, Washington, D.C.

Carl Zimmer

for National Geographic

Published August 31, 2014

A hundred years ago on Monday, a once-mighty species became extinct. At the Cincinnati Zoo, a passenger pigeon named Martha died at the age of 29.

People coming to the zoo to see the last passenger pigeon were disappointed by the bird, which barely budged off its perch. As Joel Greenberg writes in his recent book A Feathered River Across the Sky, some threw sand into its cage to try to force it to walk around. But on that first day of September a century ago, Martha no longer had to put up with such humiliations.

It was a quiet end to a noisy species. As recently as the mid-1800s, deafening flocks of billions of passenger pigeons swarmed across the eastern half of the United States. But they proved no match for humans, whose rapidly advancing technology drove the birds to extinction in a matter of decades.

Other species were also spiraling toward extinction in the late 1800s, but the destruction of the passenger pigeon happened on full public display. "It became the icon of extinction," says Mark Barrow, a historian at Virginia Tech and the author of Nature's Ghosts.

A hundred years later, the passenger pigeon remains iconic and is inspiring extravagant new technological feats. One team of scientists is even trying to bring the species back from extinction, using genetic engineering and cloning. Others are analyzing bits of passenger pigeon DNA to reconstruct its lost ways of life. (Read "Bringing Them Back to Life" in National Geographic magazine.)

And whether scientists are able to bring passenger pigeons back or not, the birds may still offer lessons about keeping other species from following it into oblivion.

Martha, seen here in a 3D animation, was mounted after her death and is currently on display at the Smithsonian National Museum of Natural History.
Animation by Donald E. Hurlbert, Smithsonian Institution

A Technological Coup de Grâce

It was hard for early naturalists to imagine that the passenger pigeon could ever become extinct. But they didn't realize that a technological revolution was about to hit.

"The telegraph allowed word to go out: 'The pigeons are here,'" says David Blockstein, a senior scientist at the National Council for Science and the Environment and a founder of Project Passenger Pigeon. Thousands of hunters would then jump on newly built trains to ride out to wherever the pigeons had settled and start slaughtering them.

The hunters weren't just killing the birds to feed their families, however. Pigeons would be stuffed into barrels and loaded back onto the trains, which would deliver them to distant cities, where they'd be sold everywhere from open air markets to fine restaurants. "Technology enabled the market," says Blockstein.

Soon this technology-driven slaughter was decimating the passenger pigeon. Its decline was so worrisome that Congress passed the Lacey Act, one of the first laws to protect wildlife in the United States. The Lacey Act would eventually help protect many species, but for the passenger pigeon it came too late.

In 1900, the year in which the act was made into law, naturalists spotted a single wild passenger pigeon in Ohio. They never saw another one in the wild again.

For the next 14 years, the species clung to existence in a few zoos. But the birds proved to be poor breeders in captivity. Martha, the last of her kind, was barren.

DNA and De-Extinction

While technology spelled the doom of passenger pigeons, some scientists believe they can use technology to bring the species back. When Martha died, biologists didn't even know that genes are encoded in DNA. Now they have the technology to extract DNA from preserved passenger pigeons in museum collections.

In 2012, a group of scientists launched a project now dubbed the Great Passenger Pigeon Comeback to create cloned passenger pigeons—or at least birds genetically engineered to have passenger pigeon traits.

Two years later, on the hundredth anniversary of the species' extinction, project scientists are still hard at work. But they can't say when—or even if—the bird will fly again.

Can the red-breasted American passenger pigeon, hunted to extinction a century ago, be revived from museum specimens? Yes, say geneticist George Church of Harvard University and his colleagues.

"It's all moving forward at the speed of science," jokes Ben Novak, a project member at the University of California at Santa Cruz.

Novak and his colleagues can't extract an intact passenger pigeon genome from museum specimens. So they're hoping they can do the next best thing: retool the genome of a living bird species so that it gives rise to a passenger pigeon.

The closest living relatives of passenger pigeons are band-tailed pigeons, which live in the western United States. The project scientists hope that their museum DNA fragments will include some unique sequences that play important roles in producing passenger pigeons—whether they help build the bird's distinctive wedge-shaped tail, its red breast, or its ultra-social behavior. It may also be possible to look at living bird species with some of these traits to pinpoint their genetic basis.

Once the scientists have created a passenger pigeon-like genome, they will insert this altered DNA into reproductive cells in band-tailed pigeon embryos. The birds will mature, mate, and lay eggs. And out of those eggs will emerge passenger pigeons—or at least birds that are a lot like the way passenger pigeons used to be.

Reverse-Engineering a Species

Just about every step in the plan for de-extinction will take the project scientists into uncharted scientific territory. The scientists can't start editing the band-tailed pigeon genome until they have a map showing the location and sequence of all its genes. But no such map exists, so Novak and his colleagues are building one.

Nor has anyone ever cloned a bird. Next year, the project researchers hope to take some steps in that direction with preliminary experiments on reproductive cells from band-tailed pigeons.

Even if the scientists end up with a brood of passenger pigeon chicks in a few years, they will still be a long way from successfully reestablishing the species. That's because the naturalists who had the opportunity to observe passenger pigeons left a lot of open questions about the natural history of the birds.

No one knows how much of the bird's social behavior is instinctive from birth, for example, and how much they must learn from older birds within an established flock. Nor does anyone know how big a passenger pigeon population has to be to sustain itself, or what range of ecosystems can support it.

Novak and his colleagues are investigating these questions, too. "We are interested in figuring out when passenger pigeons reached their highest numbers," he says. Seeing how much passenger pigeon DNA varied among individuals over time can give him and his colleagues some clues to the size of the pigeon population over the past few thousand years. It's possible that the giant flocks that early naturalists wrote about were a peak in a long-term cycle of giant booms and busts.

It's also possible that the flocks were an unprecedented explosion brought on when Europeans pushed Native Americans out of the bird's range. Understanding the pigeon's past could help Novak and his colleagues give it a future.

Preventive Measures

Even if we never resurrect the passenger pigeon, however, Blockstein sees many lessons in its disappearance that apply to protecting threatened species today.

It's a mistake to assume that a species with a big population is immune to extinction, for example. "The endangered species category is really all based on numbers, rather than biology," he explains. Even a species with billions of members may have a biological Achilles' heel that makes it vulnerable to human pressure.

To appreciate a species' true risk, we have to understand not just its biology, but also our own technological advances. In the 1800s, the new technology included the telegraph and trains. Now it includes global positioning systems, cell phones, and huge fishing vessels. "We have factory ships that can vacuum up the ocean," says Blockstein.

A few years ago, Blockstein got a chance to meet Martha. After she died, she was packed in a 300-pound block of ice and shipped to the Smithsonian Institution, where she was dissected, stuffed, and mounted. She was moved around over the years and taken off public display in 1999.

This summer, Smithsonian curators brought her out again for a new exhibit called "Once There Were Billions: Vanished Birds of North America." You can see Martha yourself there; the exhibition will be on view until October 2015.

"You're filled with awe to see the last of its species," says Blockstein. "But there's so much more to the passenger pigeon than this last individual that ended up living out her time in a cage."

Follow Carl Zimmer on Twitter and read his science blog The Loom on NationalGeographic.com.

RELATED:

- "Bringing Them Back to Life"

- "Your De-Extinction Questions Answered"

- "The Promise and Pitfalls of Resurrection Ecology"

- "What We've Lost: Species Extinction Time Line"

- "Pictures: Extinct Species That Could Be Brought Back"

- "Opinion: The Case Against Species Revival"

31 comments
Pat Kelley
Pat Kelley

They do remind me of our family of mourning doves, we love & cherish our wooded friends. Such sweet birds.

Mark Loucks
Mark Loucks

I read several articles from various sources all on this subject, and this is the only article that mentioned that the huge population explosion in the 19th century may have been due to the effects of colonization of North America which decimated Indian populations due to disease.  There is no evidence of such huge passenger pigeon populations in

pre-Colombian archaeological sites where one would expect to find lots of passenger pigeon bones in the ancient waste.  They are not there.  Source: 1491 by Charles C. Mann

ASHLEY DAVIES
ASHLEY DAVIES

We can't save our current fauna; I live in hope that one day mankind wakes up and realises playing 'god' has never worked on a system as complex as nature.

Focusing our efforts on protecting what we have is the key to natures future.

Eric Johnson
Eric Johnson

Per the fossil record, the background rate of species extinction is about 10 to 20 species a year.
 

The U.N.: WE currently extinct 150 to 200 species A DAY!


Exponential slaughter is not a moral or a functional relationship to have with other species. Actually, it's a murder-suicide relationship.

Complexity is accelerating exponentially. Our cultural genome, the collection of coding structures we use for culture's interface with reality, is complexity inadequate. That is, our moral, religious, legal, etiquette and monetary codes can't process complex network relationship information with sufficient speed, accuracy, and power. This contributes to accruing and devastating externalities, whether obesity, extinction, political gridlock, climate change, etc.

We added writing, legal, etiquette, and monetary coding structures to our cultural genome in the transition from hunter-gatherer social structures to the exponentially more complex information architecture of city-states. We need to add to our cultural genome again.

Raphael Mawrence
Raphael Mawrence

I agree with Roopa. And remember that "even a species with billions of members may have a biological Achilles' heel that makes it vulnerable to human pressure." But I will always be a proud slug!

Roopa Shanbhag
Roopa Shanbhag

First we kill them & when it is too late, we value them. Then we make Statues. What is the purpose in bringing them back? To kill again or to have more meat? Or to pat ourselves for 'yes we killed them, but we got them back as well'. This can convey a wrong message that 'go ahead & kill more, no worries, we can get them back. Also with our advanced researches, this time it would not take a century'. 

Bringing Passenger Pigeons back will only ensure killing of other endangered species & for sure, we would have more stuffed bodies & more statues. But it would not stop killing.

Instead, spend that money & effort to spread awareness of Human greed & folly & what we are about to lose, like Tiger, Elephants..... The long Red list...

When we have marked lots of days of the Calendar towards 'Human Advancements' why not celebrate September 01 as example Human Greed & Folly..... :) & let Martha's soul rest in peace ... Also save a lot more ‘Martha’s that are on the verge of getting killed.... & the dead bodies getting stuffed……

Shawn Riddick
Shawn Riddick

warningfromgod coming to a search engine near you if you would like to avoid extinction yourself. Human beings are now killing trillions of insects every day 365 days a year. God is pissed off and a war is coming. So much for peace on earth.

Eric Mills
Eric Mills

I think those monies and efforts could be better spent on habitat protection and ensuring the survival of the thousands of plants and animals barely hanging on (thanks mostly to negative human impacts).  Reportedly, there are some 30,000 species going extinct every year due to human activities. We may be "clever," we're certainly not very "smart."


Recommended reading:  Elizabeth Kolbert's "THE SIXTH EXTINCTION" (Henry Holt & Co., NYC, 2014).  R.I.P., Martha.

John G Kaleel
John G Kaleel

Who is behind these moronic postings and how may they be censured? Better yet, why aren't those responsible for such inane comments not extinct?

Dwayne LaGrou
Dwayne LaGrou

CAN WE PLEASE GET RID OF THESE GARBAGE POSTINGS!!!

This is no place for this trash. Please go and post these elsewhere!

Dwayne LaGrou
Dwayne LaGrou

I think that their attempts at this huge task have a number of benefits besides the obvious return of an extinct species. Just imagine the information about genetics that they will learn that could help in the search to cure disease's. You have to remember that the task that they are trying to complete is just a small portion of the information gleaned from this type of research!!!

Andrew Booth
Andrew Booth

If passenger pigeons had the capacity to breed in such numbers, they would again! The same huge flocks of millions would descend on crops and cover buildings, cars and whole towns in their mess! Then they would be declared 'pests', 'a nuisance' and 'vermin' and trapped, poisoned and shot accordingly! That's exactly what happens today with the feral pigeons we see breeding so successfully in our towns, cities and every other modern environment!

The real problem once again is the paradoxical attitude of humans. One group of advocates strive to save and protect wildlife while the very next group of people takes the opportunity to destroy it! 

Only by banning the hunting and killing of all animals in any form and for any reason - and enforcing very heavy penalties as a deterrent - will animals be able to live safely in a human-dominated world. And that of course would be fantasy and completely unrealistic!

The passenger pigeon should be left in peace. Other species will evolve to fill the niche - which is the fuel that drives the engine of evolution. Stepping backwards is NOT the answer!    

Greg Spies
Greg Spies

I believe trying to reverse extinction distracts us from the new extinctions we are causing every day.  We should focus on what we can do to preserve existing habitat.  If we brought the passenger pigeon back where would their billions feed, fly and breed.  The environment has changed and the passenger pigeon no longer fits.

Roopa Shanbhag
Roopa Shanbhag

September 1, 1914 was a Tuesday. This kind of  silly mistakes are not expected from reliable sources like National Geographic.

LM Bowland
LM Bowland

And yet, it is the often ignored Mourning Dove that not only has the same physical outline, (including a tail with pointed central feathers), and similar tree-nesting habits. Both Band-tailed Pigeons and Rock Pigeons are rock-crevice nesters, hence their preference for cities and human-built artificial cliffs (high-rises).

Yet, DNA doesn't lie. Does this mean the Mourning Dove and the Passenger Pigeon achieved a similar environmental niche from different starting points?

William Bowles
William Bowles

I always wonder who pays for research like this and if this is the best use of resources for research. Surely there must be more important projects that could benefit humanity more than this one!  Seems like the public is being asked to spend lots of money on things they have no interest in and really don't understand!

David Higgins
David Higgins

Who will write about the Human Extinction?  When we are all gone because we refused to stop burning Fossil Fuels will it be the Intelligent Cockroaches that tell our Story? 

Mike N
Mike N

Sounds like Jurassic Park 4

Joe Falco
Joe Falco

how an incredibly sad (the extinction). The American Bison or Buffalo was close to extinction as well.

Stewart Brand
Stewart Brand

@Andrew Booth Passenger pigeons were a forest bird.  They weren’t around cities before and wouldn’t be in the future.    --Stewart Brand

Niki Riley
Niki Riley

@Roopa Shanbhag ... 100 years from the day the bird died would be September 1st (Monday). The day of the week has nothing to do with it.

Michael Richards
Michael Richards

@William Bowles Are you kidding?  It's an astounding thing to bring an animal back from extinction.  Monumental, in fact.  I can't understand how you could possibly have no interest.  You are a hard gentleman to impress indeed if you can't appreciate the resumption of an extinct species at the hands of science.

Kurbis Junge
Kurbis Junge

@William Bowles 

The passenger pigeon was once THE MOST ABUNDANT BIRD IN NORTH AMERICA AND POSSIBLY THE WORLD accounting for 1 out of 4 birds existing.  Our species was able to eliminate it without even intending to simply through ignorance. If nothing less, the research is there to caution.  Maybe it shows remorse and an attempt to reconcile.   And if you really care to have a better reason, the next fastest means for distant communication other than this maintenance heavy, easily interruptable system of wire, fiber, relays, and electricity we are using right here is actually that very bird.  The least we can do and maybe a wise move just in case a large solar storm rains on this parade someday.

Michael Richards
Michael Richards

@David Higgins Given the adaptability of man, it's unlikely anything short of the planet's complete physical or atmospheric destruction (and complete is not going to happen for eons) will cause mankind to be extinct.  Even with the burning of fossil fuels and the effects on the climate, man's numbers grow and will continue to.  Careful not to confuse quality of life with quantity of life.

tom hagood
tom hagood

@Stewart Brand @Andrew Booth I see no reason not to revive the passenger pigeon!

In the case of this species, it is not necessary to imagine them repopulating the wild  because they adapted very well to captivity and if nothing more, I would simply like to see what stories their genes have to tell.

My blog page about the passenger pigeon and their restoration -- -- http://redmountainblogger.blogspot.com/

Roopa Shanbhag
Roopa Shanbhag

@Niki Riley

Then it should have been quoted 'Hundred years ago , on September 01' . The way it is mentioned, sounds as if September 01, 1914 was also  a monday

clifford lonokapu
clifford lonokapu

@Michael Richards The ancient human female predicted that '...they (the human male) will cause the deaths of all the larger animals (including humans) on land and in the sea and only the smaller animals will survive.'

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