During the month of September, we celebrated a grim centennial. On September 1, 1914 Martha, the last surviving Passenger Pigeon, fell from her perch at the Cincinnati Zoo and died at age 29. Of course, this species was doomed long before 1914. The last surviving male died in captivity in 1910, leaving Martha to contemplate her lonely fate. In fact, after 1900 the only Passenger Pigeons extant survived in captivity. Wild Pigeons had gone missing late in the 19th century.
How could this happen? How could a species that was once so abundant, numbering in the billions, disappear completely during the span of a human’s lifetime? In the early 19th century 3 billion or more Passenger Pigeons inhabited North America in the land east of the Mississippi River, creating an awe-inspiring spectacle as their huge flocks moved from place to place in search of food. In 1813 Audubon described one such flock in Henderson, Kentucky. Here is Audubon’s description:
…the birds poured in in countless multitudes….The air was literally filled with Pigeons; the light of noon day was obscured as by an eclipse; the dung fell in spots, not unlike melting flakes of snow; and the continuous buzz of wings had a tendency to lull my senses to repose.
JJ Audubon, Library of America, 2001
Audubon calculated that there were over a billion birds in one of these incredible flocks.
Persecution of the Passenger Pigeons by humans was the main factor contributing to their demise. Wild Pigeons were hunted relentlessly by commercial hunters and amateurs alike. Audubon described one such “hunt” at a roosting site on the banks of the Green River in Kentucky. Hundreds of people gathered for the slaughter, surrounding the “city” of roosting pigeons. Trees were cut down or set on fire, birds were suffocated with fuming sulfur pots, thousands were knocked down by polemen, and shotguns tore holes in the dense flock knocking scores of pigeons to the ground with a single shot. The dead, wounded, and mangled pigeons were piled up in heaps, packed into barrels 300 birds to the barrel, and carted off to market. Any remaining birds on the ground were fed to the hogs. Modernity played its role in the carnage. The telegraph communicated the location of these gigantic roosts instantaneously. In addition, railroads connected rural hunting sites with urban restaurants, inns, and hotels. The pigeons never had a chance. By the early 1890’s the population of Passenger Pigeons was reduced from billions to perhaps a few million birds in widely scattered flocks.
Still a few million birds is a lot of birds. For example, a few million American Wigeon might represent a healthy, stable population. In fact, a few million cormorants might be considered excessive by some. But for Passenger Pigeons a few million birds weren’t enough. As David Quammen reminds us in his excellent book The Song of the Dodo (1997) abundance is relative. Maybe Passenger Pigeons needed more than a few million birds to find the scattered concentrations of acorns and beechnuts that kept them going. Maybe they needed the social stimulation of city-sized roosts to lay their single eggs and nurture their toothsome squabs. Perhaps a nasty winter or two further depleted the stock. And, of course, there was always relentless human persecution. Whatever. By the late 1800’s there were not enough survivors among the newborn squabs to offset pigeon mortality and Passenger Pigeons disappeared from the wild.
Unfortunately for Passenger Pigeons and for us the advent of the conservation movement was still in the future while the wild pigeon population was being decimated. A few feeble attempts by state legislatures at protecting the pigeon population were launched, but the laws that were passed were too little, too late and were poorly enforced in any case. Notions of wildlife conservation were nascent at the turn of the century. The first Audubon society was incorporated in 1905 and the first federal wildlife refuge, Pelican Island NWR in Florida, was created by Theodore Roosevelt in 1904.The Audubon Society was instrumental in securing the passage of the Migratory Bird Act in 1913 and promoted the enactment of the Federal Migratory Bird Treaty in 1918, which continues to protect waterfowl and shorebirds today. But by that time Martha was dead in her cage.
So what is the legacy of the Passenger Pigeon? On Wednesday, October 8, author and naturalist Joel Greenberg recounted the story of the Passenger Pigeon and its extinction in a lecture at Lafayette Hall on the UVM campus. Joel is the author of an excellent new book entitled A Feathered River Across the Sky: The Passenger Pigeon’s Flight to Extinction in which he recounts the complicated factors leading to the Passenger Pigeon’s demise. The salient fact is that human activities contributed mightily to their decline. Even today human activities continue to affect bird populations adversely in the form of climate change due to the burning of fossil fuels, as amply documented in a new report from the National Audubon Society. This report predicts that over half of North America’s birds will become threatened or endangered as a result of climate change before the end of the 21st century. In support of this prediction the recently released State of the Birds report currently has 230 bird species on its watch list for birds that are at risk of extinction or threatened to become so if swift conservation action is not taken. This list is growing.
On the other hand attitudes toward conservation have shifted since the 19th century. Today there are many more resources at hand that benefit birds and other wildlife. Conservation-minded organizations such as the National Audubon Society, the Nature Conservancy, the National Wildlife Federation and many others lobby vigorously on behalf of conservation. As a result of this effort federal legislation has been enacted to protect wildlife, most notably the Endangered Species Act, signed into law forty years ago this year. Furthermore, thousands of citizen-scientists participate in the Christmas Bird Count, the Great Backyard Bird Count, the National Breeding Bird Survey, and the Cornell Lab of Ornithology's eBird, providing a data base that scientists can use to track bird populations in real time. Given all this attention it is unlikely that a rapid decline in bird populations will go unnoticed. Moreover, conservation works. Witness the recovery of Bald Eagles, Peregrine Falcons, and Osprey from the ravages of DDT and the resurgence of a host of waterfowl whose populations were threatened by drought and habitat loss in the middle of the 20th century. Wetland restoration through the Federal Duck Stamp program was crucial to the success of this conservation effort.
But threats remain and we must act. The legacy of the Passenger Pigeon is the observation that common birds can disappear rapidly in the face of adverse environmental circumstances, many of which are caused by human activities. Thus, the idea of keeping common birds common is more than just a mantra. Rather, this concept embraces a philosophy that promotes the continuation of life as we know it.