This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
For nearly a minute the sky went black. Then it was over.
I was standing in a long alley between two four-story brick buildings on a clear sunny day. Suddenly, off in the bright blue sliver of horizon I could see at the end of the alley, a dark cloud started to rise. It grew quickly, raced toward me, then covered the alley so completely it blocked out the sun. The sound was deafening: flapping, warbling, bumping. The cloud was the passing of thousands of passenger pigeons, jammed together in a moving clot as big as a football field, filling me with the awe and even fear of nature.
That description could have been written in any northeastern American town 200 years ago, when the passenger pigeon swarmed the region. But I’m writing it today after actually experiencing it at a big, clever exhibit at the Massachusetts Museum of Contemporary Art, which comprises a sprawling set of large building in North Adams. There, I did indeed stand in an alleyway between two building, but the “sky” was a roof that linked them, and the throng of birds that rose and then covered me was a video projection that started at the far end of the (enclosed) alley and streaked overhead—recreating what it must have been like for my ancestors to experience the throngs when they came.
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The passenger pigeon, of course, is now extinct. It was 100 years ago today—Sept.1, 1914—that the last known individual, named Martha by her keepers, died.
During the 1700s and 1800s the passenger pigeon was by far the most common bird in North America. Estimates place them at several billion during Colonial times. The flocks seen by our forebears invoked amazement—and also solved hunger. In a lovely, short history of the species written by journalist Elizabeth Kolbert for the museum exhibit, Kolbert notes: “In an account from 1610, William Strachey, one of the earliest colonists in Virginia, described the pigeons as ‘how manie thousands’ filled the sky ‘like so many thickned clowdes.’…The colonists soon recognized the birds as an excellent food source. In 1648, a flock alit in the Massachusetts Bay Colony. It ‘proved a great blessing,’ the colony’s governor, John Winthrop, wrote, ‘It being incredible what multitudes of them were killed daily.’”
John James Audubon, himself, marveled at the species, although in at least one instance he might have also been a bit disgusted, in this account from Kolbert: “Audubon was riding through western Kentucky in the fall of 1813 when he encountered a migrating flock. ‘The light of noonday was obscured as by an eclipse,’ he wrote. ‘The dung fell in spots, not unlike melting flakes of snow.’”
The practice of eating the birds only grew with time. Selling them at markets became rampant, sparking a decline in the birds' numbers. Other human and biological factors played large roles, too. Naturalist Mark Avery explains it all in a new book, A Message from Martha: The Extinction of the Passenger Pigeon and It's Relevance Today. He summed up the causes in an interview released a few days ago by the World Science Festival:
“Cutting down half of the USA’s forests by 1870 was the main factor. Passenger pigeons nested in forests, roosted in forests, and fed on the fruits of the forest: acorns, beech mast [nuts of the beech tree], and chestnuts. But we followed that up with an industrialized slaughter of the birds—mostly for food, but also for sport—and this was aided by the invention of the telegraph, the spread of the railroads, better firearms, and the lack of regulation of hunting. It was a slaughter rather than a harvest. Trainloads of millions of passenger pigeons were sent from Wisconsin and Michigan back east to the restaurants of New York and Philadelphia.”
Evidently, the pigeon’s biology didn’t help it survive the onslaught. Avery added: “But I think it was the birds’ biology that made them vulnerable in the end. Passenger pigeons relied on ‘swamping’ natural predators when their numbers were high. When their numbers fell, they just couldn’t cope with the toll taken by hawks, raccoons, squirrels, falcons, bears, and other predators.”
By the end of the 1800s naturalists tried to save the last of the species in captivity, but the efforts faltered. The final individual, which they named Martha, died at the Cincinnati Zoo on September 1, 1914.
The hundredth anniversary of Martha’s death is a sad occasion but it is also marked by an intriguing possibility. Ben Novak, a researcher at the University of California, Santa Cruz, is trying to use genetics to bring them back from the dead. As a recent article by my colleague David Biello explains, Novak has sequenced the genomes of 32 birds that are preserved at various museums and labs and is inserting edited version of those genomes into living band-tailed pigeons, a close relative.
If he succeeds—and that’s a big if—Martha's newly created kin could one day darken the skies again.
