A Century of Extinction

By Elizabeth Kolbert, The New Yorker

31 August 14

t’s unusual to be able to date the vanishing of a species. The last time a dodo was seen, on the island of Mauritius, was probably in 1662, but no one knows how long the bird survived, unseen and in low numbers. The last confirmed sighting off a great auk took place on an island off Iceland, in 1844, but it’s likely that stray birds lived on for years, even decades. There have been no confirmed sightings of the ivory-billed woodpecker since 1969, but there are still those who maintain there are ivory-bills out there somewhere.

The extinction of the passenger pigeon is one of those unusual cases, and it happened a hundred years ago this Labor Day weekend. On September 1, 1914, Martha, a passenger pigeon who lived in an aviary at the Cincinnati Zoo, was found dead in her cage. At the time, Martha was believed to be the sole passenger pigeon left on Earth, and, in the intervening century, no evidence has emerged to contradict this. The passenger pigeon was once the most numerous bird in North America, perhaps in the world; it’s estimated that when the first European settlers arrived, at least one of every four birds on the continent was a passenger pigeon. The early colonists were awed by the vastness of the flocks, which contained hundreds of millions—perhaps billions—of birds. As late as the eighteen-seventies, passenger pigeons still could be seen passing overhead in astonishing, sky-darkening numbers; then, over the course of just four decades, the species, Ectopistes migratorius, dwindled down to Martha and her companion, a male named George. Then it was just Martha. And then there were none.

The passenger pigeon’s demise is usually represented as the result of remorseless slaughter, which it certainly was. But the bird’s story also contains an element of mystery, which in some ways is just as alarming.

Passenger pigeons roosted the way they migrated, in enormous flocks. This made them easy pickings for hunters, and the early English colonists wrote of killing hundreds at a go. Once the railroads were laid, the pigeons could be shipped to big-city markets, and the butchery reached a new level. In his book “A Feathered River Across the Sky” (reviewed in this magazine and in The New York Review of Books in January), the author Joel Greenberg describes one of the last great nesting colonies, which was sighted in northern Michigan, in 1878. Telegraph operators relayed the location of the flock to hunters and trappers hundreds of miles away, and soon so many descended on the area that “hotels and boardinghouses ran out of space.” Within a few days, more than a million birds were dispatched.

By the eighteen-nineties, the only passenger pigeon sightings were of small, ragged flocks. And this is what makes the bird’s extinction difficult to entirely explain. Once the passenger pigeon was no longer abundant, it also was no longer worth hunting, or at least no more worth hunting than any other medium-sized bird. So why didn’t it persist at low densities? In his recent book “Lost Animals: Extinction and the Photographic Record,” Errol Fuller, a British author, argues that an “additional factor” must have been at work in the species’ extinction, because “in a land as vast as the United States there can be no mopping-up hunting for a species as small as a pigeon.” (Fuller’s book contains a grainy and not particularly flattering photo of Martha standing in her cage in Cincinnati.)

Some have argued that the “additional factor” was deforestation; by this account, it’s no coincidence that the passenger pigeon went extinct right about the same time that land clearing in the eastern U.S. reached its maximum extent. Others speculate that the passenger pigeon was one of those animals that require great densities to survive. One version of this theory holds that the birds mated only in great swarms; another, that the sheer scale of the flocks had protected the birds from predation.

Whether any of these “additional factors” actually contributed to the bird’s extinction is probably impossible to settle at this point. But whatever happened, the mystery should give us pause. Species that seem today to be doing fine may be sensitive to change in ways that are difficult to foresee. And we are are now changing the planet at a speed that’s probably unprecedented in at least sixty million years.

In honor of the anniversary of Martha’s death, the Smithsonian has put her taxidermied body on exhibit. (It’s usually kept in a vault.) The Massachusetts Museum of Contemporary Art, in North Adams, Massachusetts, is showing a video installation that mimics the flight of hundreds of thousands pigeons passing overhead, and next month, the Yale Orchestra will perform “The Columbiad,” a hundred-and-fifty-year-old symphony inspired by the sight of a flock.  (A century and a half ago, passenger pigeons were grouped together with rock pigeons in the genus Columba; they have since been reclassified.) All these efforts to mark the anniversary are double-edged: commemorations composed by the culpable. As the naturalist Aldo Leopold wrote in “On a Monument to the Pigeon,” composed in 1947, “For one species to mourn the death of another is a new thing under the sun. … To love what was is a new thing under the sun, unknown to most people and to all pigeons.”