Smithsonian ornithologist Brian Schmidt poses with Martha, an extinct passenger pigeon that will be added to an exhibit at the Smithsonian’s Natural History Museum in Washington. (Susan Walsh/AP)

Martha was the last of her kind.

When the famous passenger pigeon at the Cincinnati Zoo died 100 years ago, that species went extinct. The public and scientists were stunned.

“Here was a bird like the robin, that everybody knew, and within a generation or two it was gone — and we were its cause, “ Duke University ecologist Stuart Pimm said.

But now Martha is back, in a way.

The gray-and-brown bird is being taken out of the file cabinets of history and into a new exhibit at the Smithsonian’s National Museum of Natural History, reminding the public of her death and of other species that have gone extinct because of humankind. A scientific study last week showed how pigeon populations rose and fell, but also how people killed off the species.

And some scientists are even working on the long-shot hope of reviving the passenger pigeon from leftover DNA in stuffed birds.

In the 18th and 19th centuries, the wild passenger pigeon was the most abundant bird species on Earth. In 1866 in Ontario, one flock of billions of birds, 300 miles long and one mile wide, darkened the skies for 14 hours.

They were easy to catch because they stayed together. They were considered a poor person’s food.

“Nobody ever dreamed that a bird that common could be brought into extinction that quickly,” said University of Minnesota evolutionary biologist Bob Zink.

Examination of the passenger pigeon’s genetic code shows that its population ping-ponged regularly from as high as 5 billion to as low as tens of millions, said the new study, co-authored by Zink. Still, the chief causes of the extinction — the cutting down of Eastern U.S. forests and hunting — were the work of people, Zink said.

By 1900, there were no passenger pigeons left in the wild. By 1914, there was just 29-year-old Martha at the Cincinnati Zoo. People lined up to see her. She was a star.

Then on September 1, 1914, Martha’s body was found lying on the bottom of her cage. The passenger pigeon had gone from billions of birds to zero in about a century.

“This was a real wake-up call for the public and, frankly, for scientists, too,” said Helen James, curator of birds at the natural history museum. “Ornithologists studied birds, and they didn’t really think of species becoming extinct.”

But they did. Martha was shipped to the Smithsonian. She was stuffed and mounted, continuing as a star.

But her star faded. For the past 15 years, she has been in a metal filing cabinet. Last week a prettied-up Martha was ready for a comeback. An exhibit called “Once There Were Billions: Vanished Birds of North America” opens Tuesday.

And there might be a bigger comeback in the offing. The passenger pigeon is the prime candidate for something called de-extinction.

Top geneticists in a nonprofit organization are looking to see if they can create new, living versions of the passenger pigeon by editing the DNA of the closely related band-tailed pigeons, growing those birds from embryos and breeding them.

It would cost millions and take at least a decade, said Ben Novak, lead researcher of the group, Revive & Restore of San Francisco.

Novak said the huge effort might teach a lesson: “It’s so much easier to keep something alive than to bring it back to life.”

Associated Press