The very last passenger pigeon on earth was a female named Martha who lived at the Cincinnati Zoo. She was born sometime in 1895 or 1897, or perhaps 1900 or 1902, maybe at the zoo or maybe one state over, in Illinois; over the years, many different versions of her story have been offered. (As a Wisconsin naturalist once put it, “It would be difficult to find a more garbled history than that of Martha.”)

Like all passenger pigeons, Martha was a slim, elegant bird, with long tapering tail feathers and a narrow black bill—a far cry from the crumb-fed rock pigeons of urban America. (Had she been male, she would have sported greenish-blue display feathers; as it was, she was mostly brown.) Just a few decades before her birth, Martha’s was the most common bird species in North American—perhaps in the world—with individual flocks containing up to or even beyond a billion members.

Martha became the last of her kind upon the death of her companion, George, who also lived at the Cincinnati Zoo. The two occupied a cage ten feet wide by twelve feet long and were fed on cracked corn, wheat, and cooked liver. Whether or not they ever mated is unknown; like the Washingtons, they remained without issue. After George passed away, in July 1910, officials at the Bronx Zoo tried to convince officials at the Cincinnati Zoo to send Martha to New York. They refused.

Martha lingered on in Cincinnati, growing weaker at the same time that she grew more famous. A reporter who visited her in her final, solitary years described her as “atremble with the palsy of extreme old age.” Zoo-goers who came to see the elderly bird were disappointed because she barely moved. To prod her to get up and walk around, they tossed sand at her. To give her some peace, her keepers roped off her cage. They lowered her perch to within inches of the ground.

On August 29, or possibly three days later, on September 1, 1914, Martha died. It’s been claimed that at the moment of her death she was “surrounded by a hushed group of distinguished ornithologists,” but it’s more likely that she expired alone and was later found lying on the floor. The zoo director’s son delivered her fifteen-inch-long body to the Cincinnati Ice Company, where it was frozen into a three-hundred-pound block. The bird cube was then sent by rail to the Smithsonian, where Martha’s internal organs were removed and her skin preserved. In time for the centennial of Martha’s death—whenever, exactly, that was—Joel Greenberg, a Chicago-area naturalist and avid birder, has written a new account of the passenger pigeon’s demise, A Feathered River Across the Sky. As Greenberg relates it, in calm, measured prose, it’s a story of unremitting, wanton, continental-scale destruction: in a matter of about four decades, the billion-member flocks were reduced to George and Martha. By the time anyone bothered to try to protect the passenger pigeon, there were too few members of the species left for protection to make any difference. This is obviously a cautionary tale, though one whose lessons, it seems, can easily be misinterpreted.

Some sense of what it was like to watch a flock of passenger pigeons pass overhead comes from the accounts of America’s early colonists. William Strachey, an English gentleman, was sailing to Virginia on board the Sea Venture when it foundered off Bermuda in 1609. (His chronicle of the wreck is believed to have inspired The Tempest.) Strachey finally made it to the colony the following year and described pigeons of he knew not “how manie thousands” filling the sky “like so many thickned clowdes.” In 1631, Thomas Dudley, of Salem, Massachusetts, wrote of pigeons flying overhead in such numbers “that they obscured the light. It passetth credit,” he acknowledged, “but the truth should be written.” Greenberg estimates that when the first Europeans arrived in North America, at least one out of every four birds on the continent was a passenger pigeon, and perhaps as many as four out of ten.

Carl Linneaus originally placed the passenger pigeon in the genus Columba, along with rock pigeons, and called the bird Columba migratoria. The species was later moved to its own genus, Ectopistes—the word is derived from the Greek for “wandering”—and became known as Ectopistes migratorius. Like most migratory birds, Ectopistes migratorius flew south for the winter and north for the summer, but the birds’ travels were often unpredictable, and one writer dubbed them “the gypsies of birdom.” (The bird’s common name comes from the French pigeon de passage.)

Of course, what looked to humans like motiveless wandering looked very different to the animals involved. According to Greenberg, the birds’ movements were dictated by want. The prodigious flocks required prodigious amounts of food, which they found in the nuts of trees like beeches and oaks. Beeches and oaks produce big crops of nuts, or “mast,” only irregularly, so the foraging flocks had to hopscotch across the countryside to find enough to eat. When a flock came across a favorable spot and settled down, the weight of so many roosting pigeons could topple trees. The great, flapping mass was seen by some as a bad omen.


“It is a common observation in some parts of this state,” one Pennsylvanian wrote, “that when the pigeons continue with us all the winter, we shall have a sickly summer.” Mostly, though, the birds were viewed as good eating. In August 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.” It was typical, according to Winthrop, “for one man to kill eight or ten dozen in have a day, yea five or six dozen in at one shoot.” Native Americans also seem to have bagged tremendous numbers of birds whenever the opportunity arose. In 1701, a British naturalist and writer named John Lawson led an expedition out of Charleston to explore the Carolina backcountry. Lawson reported that the natives in the area used pigeon fat the way the Europeans used butter. When pigeons were roosting in the area, he wrote, “the Indians take a Light, and go among them in the Night, and bring away some thousands, killing them with long Poles.”

In spite of all this, passenger pigeons remained spectacularly abundant well into the nineteenth century. John James Audubon was riding through western Kentucky in the autumn 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; and the continued buzz of wings had a tendency to lull my senses to repose.” The birds were still flying when he stopped for the night, and they continued streaming overhead for three days solid. Audubon calculated the size of that flock at 1.1 billion, probably a reasonable estimate.

Over the next few decades, the new nation industrialized, which was good for commerce and bad for the birds; Greenberg argues that the road to the passenger pigeon’s ruin was lined with track. A growing network of railroads meant that even pigeons from relatively remote areas could be profitably transported to big city markets. An illustration of the changing business model comes from two brothers, Joseph and Isaac Allen, who lived in Michigan. One year in the mid-1850s, the boys’ father sent them to a local market with six hundred birds and instructions to offer them for a dime a dozen. The two soon realized they could make a lot more money shipping pigeons to New York. The first year they did so, they made seventy cents a dozen, and the price kept going up from there.

“The pigeon business was very profitable for men who were used to it,” they reported. And with the increasing profits came increasingly elaborate forms of slaughter. Huge net traps were strung across the forests. “Netters would not even bother springing their traps if the likely haul was less than forty or fifty dozen,” Greenberg writes. To attract flocks, the netters would keep some birds alive to use as bait—hence the term “stool pigeon.” Stoolies were fitted with tiny boots that kept their feet fixed to a contraption that functioned a bit like a see-saw. When a pigeoner wanted to lure in a passing flock he would, using a long cord, jiggle the seesaw, and the stool pigeon would appear to be hovering.

Telegraph lines were often laid alongside railroad tracks and these turned out, as far as the birds were concerned, to have a similarly baleful effect. Rapid interstate communication transformed what had been a local and, owing to the pigeon’s unpredictable movements, haphazard enterprise into a much more efficient, data-driven industry. When a flock was sighted, Greenberg writes, “the agents who staffed the rail stations made it their business to spread the word” and this soon drew trappers “from far and wide.” In 1878, there were still enough passenger pigeons to form a nesting colony that stretched over the better part of three northern Michigan counties—and that attracted a boomtown-like crowd of netters, dealers, agents, and “trollops.”

So many pigeoners and would-be pigeoners descended on the region, Greenberg writes, that “hotels and boardinghouses ran out of space” and “any boy who wanted to could find a job plucking.” It’s been estimated that in this particular frenzy, something like 1.5 million birds were killed. The result, perhaps not surprisingly, was self-defeating; the market became so glutted with pigeons that some merchants were reduced to giving them away for free.


By the mid-1890s, the only reported sightings of passenger pigeons were of straggly groups that numbered at most in the dozens. Greenberg discovers some previously unpublished records that establish that there were still pigeons left in the wild until 1902. (One of these was shot in April of that year in Indiana; its body was stuffed, but subsequently lost.) In 1907, Theodore Roosevelt, then president, claimed to have seen a group at his retreat in central Virginia; Greenberg, however, is skeptical of this report. He quotes a naturalist named A.W. Schorger, whose 1955 book The Passenger Pigeon: Its Natural History and Extinction is still the definitive source on the subject: “No better example of eternal hope, so characteristic of man, can be found than the search for a living wild passenger pigeon long after it had ceased to exist.”

Collection of Garrie Landry

A male and a female passenger pigeon; print by John James Audubon

The extinction of the passenger pigeon was an event witnessed, in a manner of speaking, by millions of people. And yet it remains a puzzle. Clearly a species that’s routinely being slaughtered as it tries to reproduce is a species that’s going to have trouble maintaining its numbers. But many have argued that hunting by itself is insufficient to explain the bird’s total loss. The reasons for this have to do with the same dynamics that drove the slaughter in the first place.

In huge, roosting flocks, the passenger pigeon was easy pickings. As its numbers fell and the great sky-darkening masses dwindled to groups of a few dozen, presumably pigeons became more difficult to find. At that point, the species should have been no more susceptible to hunting than any other medium-sized bird. (The question of whether passenger pigeons were tasty or just satiating is an open one; while some accounts hold that roasted they were quite succulent, others describe them as tough and not particularly flavorful.) Errol Fuller is an English writer and artist who has written several books on extinct birds. His latest work, Lost Animals: Extinction and the Photographic Record, includes a chapter on passenger pigeons and a grainy photo of Martha sitting on her perch at the Cincinnati Zoo. Fuller maintains that “an additional factor” must have been at work in the species’ demise because “in a land as vast as the United States there can be no mopping-up hunting operation for a species as small as a pigeon.”

In the century since Martha’s death, many “additional factors” have been proposed to solve this puzzle. One theory as to why scarcity did not save the passenger pigeon is that scarcity itself was the problem. Some have speculated that the birds took their signal to breed from other birds, so as the huge nesting colonies disappeared, the remaining pigeons essentially lost interest in sex. (This could explain why the few groups that were taken into captivity, including George and Martha’s, did not sustain themselves.)

A variation on this hypothesis holds that the passenger pigeon, which laid just one egg a year, depended on large numbers to satisfy its predators. Its nests were readily accessible to animals like foxes and raccoons (just as they were to humans), so raising a new generation required producing more young than the local foxes and raccoons could eat. According to this theory, small groups of pigeons would have produced too few squabs to overcome predation.

Yet another theory holds that the “additional factor” was deforestation. Enrique H. Bucher, a biologist at Argentina’s National University of Córdoba, has noted that the passenger pigeon population seems to have collapsed in the 1880s, which, not coincidentally in his view, was right around the time that land clearing in the eastern US reached its maximum extent. Mast, an irregular source of food under the best of circumstances, thus became more and more difficult for the birds to find. “Overall, the drop in food availability that followed European colonization was of such magnitude that it is probably by itself sufficient to explain a dramatic reduction in the Passenger Pigeon population,” Bucher has written.

For his part, Greenberg isn’t much interested in the mechanics of the bird’s extinction. Even if there was some other contributing factor, he observes, this doesn’t change the outcome, nor does it alter the moral calculus. Greenberg offers the analogy of a man who is pushed off a pier. If the man doesn’t know how to swim and ends up drowning, it might be said that the proximate cause of his death was his own ignorance (or lack of buoyancy). But, “culpability and the ultimate cause remain with the one who pushed.”

Perhaps, in ethical terms, it doesn’t much matter whether overhunting was or was not the sole cause of the passenger pigeon’s extinction. Practically speaking, though, it matters a good deal. At the start of A Feathered River Across the Sky, Greenberg writes that his goal is to inform the public “about the passenger pigeon story and to use that story as a portal into consideration of current issues related to extinction, sustainability, and the relationship between people and nature.” But doesn’t the relevance of this story depend—at least in part—on why the passenger pigeon disappeared?

More than once Greenberg asserts that the passenger pigeon was a victim of bad timing. If even a small population had survived just a few more decades, he maintains, the species might well have been saved by “new laws and attitudes.” He points out that President Roosevelt established the first national wildlife refuge in 1903, and a decade later, in 1913, Congress approved the Weeks-McLean Act, which gave the federal government power to regulate the taking of migratory birds.

“If the passenger pigeon is the icon of an animal driven to extinction through deliberate, wanton, and direct human actions, the continued existence of other species proves that these new conservation measures were effective,” he writes. He cites the example of the trumpeter swan, which in the early part of the twentieth century came perilously close to being wiped out, but which, owing to a combination of stringent protections and reintroductions, has since been growing more numerous. In the latter half of the century, new threats to wildlife were recognized; for instance, Rachel Carson, in Silent Spring, documented that pesticides were killing a lot more than just pests. “Again laws were enacted and toughened,” Greenberg writes.

The moral Greenberg seems to want to extract from the passenger pigeon’s story is that “conservation measures” can work. This is a useful and important moral, but it is not clear that it is the right moral. If the pigeon required great, light-obscuring flocks to successfully reproduce, then probably as soon as the first Europeans appeared and certainly by the time the transcontinental railroad was completed, the species was already doomed. It wouldn’t have mattered whether a few stragglers managed to hold on until “new laws and attitudes” came into play, because the bird needed high densities to survive. Similarly, if deforestation was a major contributing factor, then nothing short of altering the trajectory of American settlement would have sufficed. Perhaps Greenberg is right when he suggests that a serious breeding effort could have prevented Martha from becoming “the last of her species.” But even if a captive breeding program might technically have saved the passenger pigeon from extinction, in any sense that really matters, the bird would still be gone—missing from the forests (also largely gone) where its droppings used to fall like “melting flakes of snow.”

Meanwhile, what goes for the passenger pigeon goes for the long and ever-growing list of endangered species. It’s nice to think that once a new problem is recognized, we can address it by enacting or toughening some law. But this kind of piecemeal approach—legislating against this particular practice, or that one—is inadequate to the problem, and probably has been ever since the Sea Venture was wrecked off Bermuda. Toward the end of A Feathered River Across the Sky, Greenberg runs through a litany of threats to what’s still called wildlife, though much of it isn’t terribly wild anymore: overfishing, global warming, pollution, introduced species. He discusses white-nose syndrome, a fungal disease that is devastating bat populations in the eastern US. The fungus was probably introduced from Europe, and probably inadvertently, perhaps on some tourist’s shoe.

The “deliberate, wanton, and direct” slaughter that the passenger pigeon was subjected to probably couldn’t happen today. Not only laws but, as Greenberg points out, attitudes have changed. However, extinction rates now are higher than they’ve been at any point since the dinosaurs disappeared sixty-six million years ago. The passenger pigeon, it turns out, is part of a much bigger story, a story only beginning to unfold. In this larger narrative, deliberate destruction counts less than the perfectly ordinary, seemingly benign actions of 7.2 billion people. When we tell ourselves that since Martha’s death we’ve learned to take better care of our fellow creatures, we are, sadly, kidding ourselves.